Martin Sandberg, known professionally as Max Martin, (born 26 February 1971) is a Swedish music producer and songwriter. He broke through as a producer and songwriter in the mid-1990s after crafting a string of hits for pop artists like Ace of Base, E-Type, the Backstreet Boys, Britney Spears, *NSYNC and Robyn. Some of his earlier hits include "Quit Playing Games (With My Heart)", "...Baby One More Time" and "It's My Life".

His trademark during the second half of the 1990s and the early 2000s was a danceable, keyboard-laden pop sound that blended music styles such as funk, heavy metal and europop. However, with Kelly Clarkson's 2004 hit "Since U Been Gone", Martin stepped back into the spotlight after reinventing himself with a heavier, rock-tinged sound.

Since 2008, he has written and co-written more than 10 number-one hits, including "So What" by Pink, "Hot n Cold", "I Kissed a Girl" by Katy Perry, and "My Life Would Suck Without You" by Kelly Clarkson. Since 2010, he has co-written ten top-10 singles, including "Dynamite" by Taio Cruz, "DJ Got Us Fallin' in Love" by Usher, "Whataya Want From Me" by Adam Lambert, "F**kin' Perfect" by Pink, and "Hold It Against Me" by Britney Spears.

Amethyst Amelia Kelly (born June 7, 1990), better known by her stage name Iggy Azalea is an Australian hip hop recording artist signed to Grand Hustle Records. She is perhaps better known for her promotional songs "Two Times", "Pu$$y" and "My World" whose music videos went viral on YouTube. On 27 September 2011, Azalea released her first project, a mixtape titled Ignorant Art, saying she made it "with the intent to make people question and redefine old ideals".

Iggy Azalea was born Amethyst Amelia Kelly in Sydney, Australia but moved with her family to Mullumbimby when she was still a baby, into a house on 12 acres that her father built by hand from mudbricks in New South Wales. Her father was a comic artist and painter and her mother a real estate agent. Azalea says her father "made her look at [art] as a teenager" which has always influenced her life and work.

Azalea began rapping at age 14. Azalea took her stage name from her family's dog while growing up. Before embarking on a solo career, Azalea formed a group with two other girls from her neighborhood: "I was like, I could be the rapper. This could be like TLC. I’ll be Left Eye." Azalea eventually decided to leave the group because the other girls weren’t taking it seriously: "I take everything I do serious. I’m too competitive."

Elena Jane Goulding (born 30 December 1986), known professionally as Ellie Goulding, is an English singer-songwriter. In 2010 she became the second artist to both top the BBC's annual Sound of... poll and win the Critics' Choice Award at the BRIT Awards in the same year, following Adele's win of both in 2008. After signing to Polydor Records in 2009, she released her first EP in 2009, An Introduction to Ellie Goulding, followed by her debut studio album Lights in 2010. Her album debuted at number one on the UK Albums Chart and has sold over 650,000 copies in the UK. "Lights" was released in America March 8th 2011, where the title track has been certified platinum by the RIAA (excess of 1 million units sold) .

Goulding is a soprano, and her musical style has been compared to that of Kate Nash, Meiko, Lykke Li and Tracey Thorn.

Goulding was born and brought up in a small town near Hereford, Herefordshire, the second of four children. She began playing the clarinet at the age of nine, and at 14 began learning guitar. She attended Lady Hawkins' School in Kington, where she won a main part in a school production, the Wizard Of Oz, as the scarecrow. She started songwriting at the age of 15 and while in college she won a singing competition.

Jennifer Kate Hudson (born September 12, 1981) is an American recording artist, actress and spokesperson. She came to prominence in 2004 as one of the finalists on the third season of American Idol, coming in seventh place. She made her film debut in the 2006 film Dreamgirls, which won her an Academy Award for Best Supporting Actress, a Golden Globe Award, a BAFTA Award, an NAACP Image Award and a Screen Actors Guild Award.

She won a Grammy Award for her eponymous debut album, Jennifer Hudson, which was released in 2008 on Arista Records and was certified gold by the RIAA for selling over 800,000 copies in the US; sales exceeded 1 million copies worldwide. Additionally, it spawned the hit single Spotlight. Her second album, I Remember Me, was released in March 2011, and reached number two on the Billboard 200, selling 165,000 copies in its first week of release. The album was certified gold by the RIAA, for shipping over 500,000 copies in the US.

In late 2008, after Hudson's mother, brother and nephew were killed in a shooting, Hudson stepped out of the limelight for three months. Hudson resumed her public appearances in 2009, and has since performed at the Super Bowl XLIII, the Grammy Awards, American Idol, and The Oprah Winfrey Show. Hudson has been described as a friend of President Barack Obama, who invited her to appear with him at a fundraiser in Beverly Hills in May 2009. She also performed at the White House at the "Celebration of Music from the Civil Rights Movement" event. Her vocal range is mezzo-soprano. Hudson has sold 1,280,000 albums and 2,237,000 tracks in the United States as of February 2012.

Christina María Aguilera (born December 18, 1980) is an American recording artist and actress. Aguilera first appeared on national television in 1990 as a contestant on the Star Search program, and went on to star in Disney Channel's television series The Mickey Mouse Club from 1993 to 1994. Aguilera signed to RCA Records after recording "Reflection", the theme song for the animated film Mulan (1998).

In 1999, Aguilera came to prominence following her debut album Christina Aguilera, which was a commercial success spawning three number one singles on the Billboard Hot 100—"Genie in a Bottle", "What a Girl Wants", and "Come On Over Baby (All I Want Is You)." Her sophomore and her debut Latin-pop album, Mi Reflejo (2000), a Christmas third studio album, My Kind of Christmas (2000), and several collaborations followed which garnered Aguilera worldwide success, though she was displeased with her lack of input in her music and image. After parting from her management, Aguilera took creative control over her fourth studio album, Stripped (2002). The album's second single, "Beautiful", was a commercial success and helped the album's commercial performance amidst controversy over Aguilera's image. Aguilera followed up Stripped with the soul, jazz and blues inspired, Back to Basics (2006), released to positive critical acclaim. The album produced three singles "Ain't No Other Man", "Hurt" and "Candyman". Four years later Aguilera released her sixth studio album, Bionic (2010), which incorporated aspects of R&B, electropop, and synthpop and was met with mixed reviews and low sales. Aguilera's seventh studio album is set to be released in 2012.