Nielsen's exploits were well-covered in the entertainment media in the 1980s, and the world press started referring to her as an "Amazon" because of her tall stature. She later built a career starring in B-movies and hosting TV shows, and in the 2000s, for appearing on reality shows. In 2008, she appeared on the reality show Celebrity Rehab with Dr. Drew, which depicted her and several other celebrities dealing with recovery from drug and alcohol addiction. In 2012 she won the 6th season of Ich bin ein Star – Holt mich hier raus!, the German version of I'm a Celebrity...Get Me Out of Here! and received the most calls from TV viewers throughout the entire show, ranking No.1 with 30 – 50% of all call-ins.
Nielsen was born Gitte Nielsen in Rødovre, a suburb of Copenhagen, Denmark, as the daughter of Hanne, a librarian, and Svend Nielsen, an engineer. She is also the ex-sister-in-law of Drive director, Nicolas Winding Refn.
Standing 1.85 m (6'1"), at the beginning of the 1980s, Nielsen did some modeling work, and was photographed by Greg Gorman and Helmut Newton. Nielsen posed for Playboy magazine multiple times, garnering the cover in December 1987. In the late 1980s, Marvel Comics approached Nielsen to pose for photographs dressed as the comic book character She-Hulk.
In 1985, Nielsen began her acting career in the fantasy film Red Sonja alongside Arnold Schwarzenegger. That same year, she met and married Sylvester Stallone; the couple acted in two films together (Rocky IV and Cobra) before divorcing in 1987. Their marriage and divorce were both highly publicised by the tabloid press. In 1987, Nielsen played Karla Fry in the film Beverly Hills Cop II (1987), alongside Eddie Murphy. Subsequently, she starred in 976-Evil II, The Double 0 Kid (1992), Chained Heat II (1993), Galaxis (1995), and Snowboard Academy (1996). She starred as the villainess of the Italian TV fantasy film Fantaghirò 2 and its sequels (1992–1996).
In 2011, Nielsen voice acted for the Danish animated comedy film Ronal the Barbarian. She played in the horror movie Eldorado (2012), co-starred Daryl Hannah, Michael Madsen and Kerry Washington. In 2013, she has featured in the short art film The Key alongside Ray Stevenson. In 2014, she starred in the science-fiction film Exodus, in the TV series Raising Hope, and in the action film Mercenaries (2014), alongside Cynthia Rothrock, Vivica A. Fox, and Kristanna Loken.
In 2017, she joins the cast of TV Series Adi Shankar's Gods and Secrets.
Nielsen started a music career in 1987. She released her debut album Every Body Tells a Story in that year and recorded a duet with Austrian pop star Falco, Giorgio Moroder's penned "Body Next to Body" which went to No. 22 in Germany and No. 6 in Austria. She released a follow-up album, I'm the One... Nobody Else, in 1991.
Nielsen released a few songs under the pseudonym "Gitta" because producers wanted to see if she could succeed as a singer without her name on the cover. The first song "No More Turning Back" peaked at No. 54 on the British Single Charts, No. 63 on the Dutch Single Charts and even reached the Top 10 in Spain. Other tracks recorded as Gitta were 2001's "Tic Toc" and 2002's "You're No Lady", a collaboration with Ru Paul.
Nielsen appeared in Michael Jackson's Liberian Girl music video in 1989 and in metal band Korn's music video for the single Make Me Bad in 2000. In 2008, German record label Edel Music re-released her 1991 album I'm the One... Nobody Else and the 1987 Every Body Tells a Story under the title Brigitte Nielsen. In 2012, she performed (as Gitte Nielsen) on the song "Misery" with Spleen United, from the album School of Euphoria.
In 2009, she published her first autobiography in Scandinavia titled "Gitte Nielsen – Du har kun ét liv – sådan fandt jeg tilbage til mig selv" ("You only have one life – this is how I found myself again"). The book reached the Top5 of Denmark's bestseller list and was released in the United Kingdom under the title You Only Get One Life in 2011.
Nielsen has worked for Italian television, hosting shows such as: Festival (1987), the 1992 edition of the Sanremo Music Festival, Retromarsh! (1996–1997), and ..la sai l'ultima? (1999). In 1997, she hosted a talk show series Gittes venner for a Danish TV network and some TV shows for RTSI, the Swiss television in the Italian language. She guest starred for an episode of the German TV series SOKO: Stuttgart, aired by ZDF on 28 March 2011, guest-hosted the British chat show Loose Women on 7 December 2010. In April 2011, she attended the British variety/talent show Sing If You Can, which aired on ITV.
Nielsen appeared on the first season of the Italian production of The Mole (2004) and on the third season of the VH1 reality show The Surreal Life (2004). Nielsen also appeared with Flav on VH1's Big in '04 Awards. In 2006, she guest-starred on Flav's other reality show, Flavor of Love. In 2003, Nielsen appeared in the Danish Big Brother VIP. In January 2005, she was a contestant in Britain's Celebrity Big Brother, along with her former mother-in-law, Jackie Stallone, coming third in the final public vote. In 2006, she appeared in another reality TV series, VH1's The Surreal Life: Fame Games. In 2007, she starred in a new British mockumentary Killing Brigitte Nielsen, which aired on Sky Travel. She also appeared in the first season of Celebrity Rehab with Dr. Drew, which chronicled her struggle to overcome her alcoholism at the Pasadena Recovery Center in Pasadena, California.
In May 2008, Nielsen revealed on German television that she would "renew" her body by having six plastic surgeries, which would cost €66,000 altogether. She was filmed during those surgeries by RTL and she had her own television show Aus alt mach neu – Brigitte Nielsen in der Promi-Beauty-Klinik. The same show was broadcast twice in Italy: at first under the title Celebrity Makeover: Brigitte Nielsen on SKY Italia in 2008 and secondly in 2009 on Italia 1. In 2009, Nielsen appeared as a panel speaker to a new group of addicts at the Pasadena Recovery Center, anticipating the two-year mark of her sobriety that coming July. Her appearance was aired in the third season episode "Triggers", which aired in February 2010.
In 2010, Nielsen appeared as one of the celebrity contestants of TF1 reality show La Ferme Célébrités, the French version of the TV series The Farm. She was eliminated after one week, mainly due to her lack of fluency in French and subsequent difficulties to interact with the other contestants. Nielsen was one of the celebrity contestants of 2010's Let's Dance, the German version of Dancing with the Stars. That same year, she also took part of Celebrity Come Dine With Me in Denmark (Til middag hos... ), and in Germany (Das Perfekte Promi Dinner). From 13 January 2012 Nielsen was one of the celebrity contestants and winner of Ich bin ein Star – Holt mich hier raus!, the German version of I'm a Celebrity...Get Me Out of Here!, broadcast by RTL Television. On 28 January 2012 she won the show as the "Jungle Queen". Bildzeitung revealed on 30 January 2012 that Nielsen had received the most calls from TV viewers throughout the entire show, ranking No.1 with 30 – 50% of all call-ins. Nielsen was paid 150.000 Euro (approx. $163,000) for participating in the show, more than any other celebrity.
In October 2012, Nielsen was featured in the Danish version of Maestro broadcast on DR1 in which celebrities competed for the chance to conduct a classical orchestra. In September 2013, she joined the cast of the German TV show Promi-Hochzeitsplanern (Celebrity Wedding planners) for Sat.1. The following year she joined the panel of the German TV show Promi Shopping Queen for VOX.
From June 2015 she hosts her own talk show "Gitte Talks" on the Danish TV Channel Kanal 4.
Nielsen participated in an all-stars special of Ich bin ein Star – Holt mich hier raus!, the German version of I'm a Celebrity...Get Me Out of Here! in August 2015 for one episode, in which TV viewers could vote which celebrity was going to take part in the upcoming season in January 2016. She qualified for the finale on August 5 by receiving the most phone calls and then, again, was voted by the German TV audience to participate in the upcoming season of Ich bin ein Star – Holt mich hier raus! in January 2016.
From August 2016 she presents the dating show "Wirt sucht Liebe" ("Is Looking for Love") for the German TV channel RTL II
Besides her native Danish, Nielsen is fluent in Norwegian, Swedish, English, German and Italian, and has some understanding of French.
Nielsen has been married five times and has four sons. She has a son, Julian Winding (born in 1984), with her first husband, Kasper Winding, to whom she was married from 1983–84. Nielsen married actor Sylvester Stallone, on 15 December 1985 at the Beverly Hills, California home of producer Irwin Winkler. Stallone and Nielsen's marriage lasted 19 months, with their divorce finalized July 1987. Her second child, Killian Marcus Gastineau (born in 1989), she had with ex-fiance Mark Gastineau.
Between 1990 and 1992, she was married to director and photographer Sebastian Copeland (Orlando Bloom's cousin). Nielsen has two sons with fourth husband Raoul Meyer, Douglas Aaron (born in 1993) and Raoul, Jr. (born in 1995). Her current husband, Mattia Dessi, lived with her in Italy as shown on Strange Love, which was filmed prior to their marriage. As of 2010, they live in Palm Springs, USA.
In 1987, Nielsen confessed to an affair with Tony Scott. In 2005, she had a highly publicized relationship with rapper Flavor Flav. In the aftermath of Arnold Schwarzenegger's infidelity scandal, Nielsen confessed that she also had an affair with him while he was in a relationship with Maria Shriver. In January 2012, during an interview on the German Reality TV-Show Ich bin ein Star – Holt mich hier raus!, she confessed once having a one-night stand with Sean Penn in Cannes.
On 9 July 2007, Nielsen checked herself into the Cri-Help rehabilitation facility in North Hollywood following what some reports claim was a family intervention. Her manager, Steven Tempone, confirmed on 19 July 2007 that she had checked into a rehabilitation center and told the Associated Press, "All I know is it's something she did of her own free will and we're proud of her and wish her very well... When she gets out we'll have a big birthday party, and Coca-Cola only." As of 22 July 2007, Nielsen was out of rehabilitation to attend the Comedy Central roast of Flavor Flav. She told People that she felt "like a new-born person ... I made a choice about a new life. It's not been easy but it was definitely time." While People does not report the date that Nielsen checked into rehabilitation, it states she "had been in treatment for a few weeks."
On 10 January 2008, VH1 began airing the reality TV series, Celebrity Rehab. Nielsen appeared on the show for alcoholism. In a January 2010 TV Guide story on her success with sobriety, Celebrity Rehab producer John Irwin stated, "She's sober, and she quit smoking. She's doing crazy good."
In mid-2008, Nielsen starred in the reality show Aus alt mach neu, broadcast by the German TV-station RTL. The theme of the show was Nielsen's attempt to look "as young as her husband" by undergoing plastic surgery. The show was aired in Italy as well, on SKY Italia during December 2008 and the following summer on Italia 1.1988 Every Body Tells a Story1992 I'm the One... Nobody Else2008 Brigitte Nielsen (re-release of I'm the One... Nobody Else and Every Body Tells a Story)"Body Next to Body" – Falco meets Brigitte Nielsen; 1987; (No. 6 Austria, No. 22 Germany, No. 1 Japan)"Every Body Tells a Story"; 1987; (No. 38 Italy; No. 15 Germany)"Maybe"; 1988"Siento"; 1988 (South America only)"It's a Strange Love"; 1988"Rockin' Like a Radio"; 1990"My Girl (My Guy)"; 1991"How Could You Let Me Go?"; 1992"Work That Body"; 1993"No More Turning Back" (as Gitta); 2000; released by Jive; (No. 1 Spain, No. 1 Eurodance chart; No. 64 Netherlands, No. 54 UK)"Everybody's Turning Back" (as Gitta vs. Rozalla)"Tic Toc" (as Gitta); 2001; released by Blanco y Negro"You're No Lady" (as Gitta with Ru Paul); 2002; released by Do It Yourself; (No. 1 Spain)"Misery" (as Gitte Nielsen with Spleen United); 2012