In popular music, a cover version or cover song, or simply cover, is a new performance or recording of a contemporary or previously recorded, commercially released song or popular song. It can sometimes have a pejorative meaning implying that the original recording should be regarded as the definitive or "authentic" version, and all others merely lesser competitors, alternatives or tributes (no matter how popular). Originally, Billboard and other magazines which track the popularity of the musical artists and hit tunes measured the sales success of the published tune, not just recordings of it. Later, they tracked the airplay that songs achieved, for which some cover versions are the more successful recording(s) of the particular song(s). Cover versions of well known, well liked, tunes are often recorded by new artists to achieve initial success when their unfamiliar original material would be less likely to be successful. Prior to the onset of Rock 'n' Roll in the 1950s, songs were published and several records of a song might be brought out by singers of the day, each giving it their individual treatment. Any singer who appeared to be copying an already successful version of the song would be viewed with disfavour. The trend, however, became for records to be produced, usually with particular background noises, and no other group would attempt a version.

Peter Gene Hernandez (born October 8, 1985), better known by his stage name Bruno Mars, is an American singer-songwriter and record producer. Raised in Honolulu, Hawaii by a family of musicians, Mars began making music at a young age. He performed in various musical venues in his hometown throughout his childhood. He graduated from high school and then moved to Los Angeles, California to pursue a musical career. Mars produced songs for other artists, joining production team The Smeezingtons.

Mars had an unsuccessful stint with Motown Records, but then signed with Atlantic Records in 2009. He became recognized as a solo artist after lending his vocals and co-writing the hooks for the songs "Nothin' on You" by B.o.B, and "Billionaire" by Travie McCoy. He also co-wrote the hits "Right Round" by Flo Rida featuring Ke$ha, and "Wavin' Flag" by K'naan. In October 2010, he released his debut album, Doo-Wops & Hooligans. Anchored by the worldwide number-one singles "Just the Way You Are" and "Grenade", the album peaked at number three on the Billboard 200. Mars was nominated for seven Grammys at the 53rd Grammy Awards, winning Best Male Pop Vocal Performance for "Just the Way You Are".

Pierre David Guetta (7 November 1967), known professionally as David Guetta (French pronunciation: [daˌvid ɡɛˈta]), is a French house music producer and DJ. Originally a DJ at nightclubs during the 1980s and 1990s, he co-founded Gum Productions and released his first album, Just a Little More Love, in 2002. Later, he released Guetta Blaster (2004) and Pop Life (2007). His 2009 album One Love included the hit singles "When Love Takes Over" (featuring Kelly Rowland), "Gettin' Over You" (featuring Chris Willis, Fergie & LMFAO) and "Sexy Bitch" (featuring Akon), the last becoming a top five hit in the United States and all three reaching #1 in the United Kingdom, as well as another internationally known single called "Memories" featuring Kid Cudi which became a top five hit in many countries. Guetta has sold over three million albums and 15 million singles worldwide. He is currently one of the most sought-after music producers. As at 2012 David Guetta is the world's most popular DJ, claiming the #1 poll position of the DJ Mag 100 popularity poll.

Justin Randall Timberlake (born January 31, 1981) is an American singer, actor, and businessman. He achieved early fame when he appeared as a contestant on Star Search, and went on to star in the Disney Channel television series The New Mickey Mouse Club, where he met future bandmate JC Chasez. Timberlake became famous in the late 1990s as the lead singer and youngest member of the boy band 'N Sync, whose launch was financed by Lou Pearlman.

In 2002, he released his debut solo album, Justified, which sold more than seven million copies worldwide. The album was a commercial success, spawning the hits "Cry Me a River" and "Rock Your Body". Timberlake continued his success with his second solo album, FutureSex/LoveSounds (2006), debuting at number one on the Billboard 200 chart, and produced the US number-one hit singles "SexyBack", "My Love", and "What Goes Around... Comes Around".

Timberlake has won six Grammy Awards and four Emmy Awards. His first two albums made him one of the most commercially successful singers in the world, each selling in excess of 7 million copies. He also has an acting career, having starred in films such as The Social Network, Bad Teacher and Friends with Benefits. His other ventures include record label Tennman Records, fashion label William Rast, and the restaurants Destino and Southern Hospitality.

Pharrell Williams (born April 5, 1973), commonly known simply as Pharrell, is an American rapper, singer, record producer, composer, and fashion designer. Williams and Chad Hugo make up the record production duo The Neptunes, producing hip hop and R&B music. He is also the lead vocalist and drummer of hip-hop band N.E.R.D, which he formed with Hugo and childhood friend Shay Haley. He released his first single "Frontin'" in 2003 and followed up with his first album In My Mind in 2006.

As part of The Neptunes, Williams has produced numerous hit singles for various musicians. The two have earned three Grammy Awards amongst ten nominations. He is also the co-founder of the clothing brands Billionaire Boys Club and Ice Cream Clothing. He is a member of the supergroup V.A. Playaz with Fam-Lay, Clipse, Skillz, Missy Elliott, and Timbaland & Magoo.

Pharrell Williams was born on April 5, 1973, in Virginia Beach, Virginia, the eldest of three sons of Carolyn, a teacher, and Pharaoh Williams, a handyman. He met Chad Hugo in a seventh-grade summer band camp where Williams played the keyboards and drums and Hugo played tenor saxophone. They were also both members of a marching band; Williams played the snare drum while Chad was student conductor. With Hugo, Williams attended Princess Anne High School where they played in the school band; there he got the name Skateboard P.