Stephanie Lynn Pratt (born April 11, 1986) is an American reality television personality. She is known best for her role as a cast member on MTV's The Hills.

Pratt began her role on The Hills in Season 3, in 2007, as Spencer's angry sister who confronted Lauren Conrad. She eventually apologized to Lauren and became one of her close friends, causing a rift between her and Spencer. In Season 4, Stephanie's role increased and the show focused on her personal life and her past drug abuse. In Season 5, Stephanie worked with Lauren at People's Revolution, but she was a terrible employee and Kelly Cutrone ordered Lauren end Pratt's internship, after which Stephanie vacillated between being astonished that her "good friend" Lauren would have let her go and accepting of how her incompetence made the firing justified. Pratt became close friends with Audrina and Lo following Lauren Conrad's departure and Kristin Cavallari's new role in the series. Even though Pratt and Cavallari began as rivals due to conflicts about Audrina's ex-boyfriend and a report linking Cavallari to drug use, they soon became best friends.

Kelly Cutrone (born November 13, 1965) is an American fashion publicist, television personality, and author.

Cutrone was born and raised in Camillus, New York. She attended West Genesse High School, and in 1988 graduated from Syracuse University.

Cutrone has been married twice. At 24, she married Andy Warhol's protégé, artist Ronnie Cutrone, and at 33, married Jeff Kober. Both marriages ended in a divorce. She has a daughter with Ilario Calvo, Ava Cutrone-Calvo (born 2002).

Cutrone left for New York at 21, and began her career in public relations after having been introduced to Susan Blond (a prominent New York publicist) by acquaintance, writer and socialite Anthony Haden-Guest, who had suggested that she become a publicist. Cutrone was Blond's assistant, she recalled, "for six to eight months", until she went on to become director of PR at Spin magazine for Bob Guccione, founder of the adult magazine Penthouse. Less than a year later, frustrated with the lack of power she held at the company, Cutrone set up her own company, Cutrone & Weinberg, with former Susan Blond intern Jason Weinberg. Among their clients were Eartha Kitt, the Smithereens and Whole Earth Mamas.

Stefani Joanne Angelina Germanotta (/ˈstɛfəniː dʒʌrməˈnɑːtə/ STE-fə-nee jurr-mə-NAH-tə; born March 28, 1986), known by her stage name Lady Gaga, is an American singer and songwriter. Born and raised in New York City, she primarily studied at the Convent of the Sacred Heart and briefly attended New York University's Tisch School of the Arts before withdrawing to focus on her musical career. She began performing in the rock music scene of Manhattan's Lower East Side, and was signed with Streamline Records by the end of 2007. During her employment as a songwriter for the record company, her vocal abilities captured the attention of recording artist Akon, who signed her to his label Kon Live Distribution.

Lady Gaga came to prominence as a recording artist following the release of her debut album The Fame (2008), which was a critical and commercial success that topped charts around the world and included the international number-one singles "Just Dance" and "Poker Face". After embarking on the The Fame Ball Tour, she followed the album with The Fame Monster (2009), which spawned the worldwide hit singles "Bad Romance", "Telephone" and "Alejandro". The album's success allowed her to embark on the eighteen-month long Monster Ball Tour, which later became one of the highest-grossing concert tours of all time. Her most recent album Born This Way (2011) topped the charts of most major markets and generated more international chart-topping singles, including "Born This Way", "Judas" and "The Edge of Glory". Besides her musical career, she involves herself with humanitarian causes and LGBT activism.

Ryan John Seacrest (born December 24, 1974) is an American radio personality, television host and producer. He is known internationally as host of the top-rated primetime talent showcase American Idol. He has been nominated for an Emmy award in the "Outstanding Host for a Reality or Reality-Competition Program" category for his work on American Idol. He won a Daytime Emmy Award for co-hosting the 2005 Walt Disney World Christmas Day Parade with Regis Philbin and Kelly Ripa. As a television producer, Seacrest has won an Emmy for the ABC show Jamie Oliver’s Food Revolution. On radio, Seacrest is host of On Air with Ryan Seacrest, his market-topping #1 nationally syndicated LA morning drive-time radio show for Clear Channel’s 102.7 KIIS-FM. , as well as a nationally-syndicated Top 40 radio show. Seacrest hosted the 59th Primetime Emmy Awards on September 16, 2007. Seacrest has extensive deals with brand heavyweights Proctor & Gamble, Coca-Cola and Microsoft, and has a strategic marketing and technology alliance with Eventful, Inc.

Kristin Elizabeth Cavallari (born January 5, 1987) is an American television personality and actressof italian origin. She is best known for her starring roles on the former MTV reality television programs Laguna Beach: The Real Orange County and its spin-off, The Hills.

Cavallari was born in Denver, Colorado, the second of two children of Judith Spies (née Eifrig) and Dennis Cavallari.

When her mother divorced her father, her older brother, Mike, moved with their father to Laguna Beach, California, while she moved with her mother to the village of Barrington, Illinois, a suburb an hour northwest of Chicago. She attended Barrington Station Middle School, and graduated on to Barrington High School. After difficulties adjusting to a new life with a stepfather and stepbrother, Cavallari moved to California to live with her father. There, Cavallari was enrolled at Santa Margarita Catholic High School for her sophomore year. After she attended a Driver's Education course through Laguna Beach High School, her father enrolled her in Laguna Beach High School.