Holly Madison hosts a Fourth of July party at the Wet Republic Pool

Holly Madison Cullen (born December 23, 1979) is an American model and television personality, best known for appearing as Hugh Hefner's number one girlfriend with Bridget Marquardt and Kendra Wilkinson on the reality television series The Girls Next Door. Although not a Playboy Playmate, she has appeared in nude pictorials with her Girls Next Door costars and fellow Hefner girlfriends Bridget Marquardt and Kendra Wilkinson. In 2009 she was as a contestant on the eighth season of Dancing with the Stars.

Madison was born Hollin Sue Cullen in Astoria, Oregon. Her father traveled around due to work in the timber industry, and from ages two through eleven, she grew up on Prince of Wales Island, Alaska, near Ketchikan. Her family then moved back home to St. Helens, Oregon. She attended Portland State University for two years as a double-major in theatre and psychology.

In 1999, Madison moved to Los Angeles to attend Loyola Marymount University.

To afford college tuition, she competed to become a Hawaiian Tropic model and worked at Hooters. After being noticed, she began to receive invitations to the Playboy Mansion. After more than a year of visiting the mansion, Madison was invited to move in. She became one of Hefner's seven official girlfriends in August 2001. In February 2002, after all but two of his girlfriends left, Madison became Hef's "#1 Girl" and moved into his bedroom at the mansion. She was named among the top Hooters girls of all time in 2008 as part of the restaurant's twenty-fifth anniversary.

Madison has spoken openly about her plastic surgery, having had a rhinoplasty (nose job) and breast augmentation, going from a size A-cup breast to a D-cup. She had only one tattoo, a red Playboy Bunny logo on her lower back but later had it removed

In 2003, Madison shot a pictorial for Cyber Girl of the Week, a feature of the Playboy website. She also appeared on the cover and inside of the November 2005 issue of Playboy magazine, along with Marquardt and Wilkinson as part of a special pictorial promoting The Girls Next Door. The girls were featured again on the covers of the September 2006, March 2008, and the February 2009 issues of Playboy.

In the Season 3 episode "My Bare Lady", Madison stated that she wanted to have a career producing Playboy spreads. During seasons three and four, Holly was shown working at the Playboy studios as an intern and later a junior photo editor. She also helped design and put together The Girls Next Door 2008 calendar.

A self-described animal lover, Madison started writing articles about pets in 2006 for a friend's quarterly magazine, The Coolest Little Pet Magazine. She describes herself as "mistress of the Mansion pooches". In April 2007, Madison was featured nude in a PETA advertisement, with the tagline "I'd rather go naked than wear fur".

In February 2009 she quit working for the company all together due to the split from Hefner making her position "awkward".

In 2009, Madison attempted a Guinness World Record rallying women from all over Las Vegas to hold the World's "largest bikini parade ever", winning the title.

Madison was chosen to replace Jewel Kilcher on Dancing with the Stars after Kilcher was forced to withdraw (along with Nancy O'Dell) due to injuries sustained during rehearsal. She partnered with Dmitry Chaplin. On March 31, 2009 Holly and Dmitry were voted off the show in a double elimination episode.

Madison stars in topless burlesque show Peepshow at Planet Hollywood in Las Vegas. She was brought in to replace Kelly Monaco after Monaco's three month contract was up. Madison was likewise initially signed to a three month contract, but she has since extended her contract to a full year.

Like former The Girls Next Door co-star, Kendra Wilkinson, Madison stars in her own reality show, Holly's World, which revolves around her life at Planet Hollywood in Las Vegas. "It's all good-natured and not mean like other reality shows," Madison said of her show. "I'm really excited about the new series because I am also getting a legitimate co-producer credit for all the work I do behind the camera. It's not a vanity credit. I'm super excited to learn from the best and take on new responsibilities." The show premiered with a "preview episode" on December 6, 2009, but will not start airing regularly until June 2010