Singing is the act of producing musical sounds with the voice, and augments regular speech by the use of both tonality and rhythm. One who sings is called a singer or vocalist. Singers perform music known as songs that can be sung either with or without accompaniment by musical instruments. Singing is often done in a group of other musicians, such as in a choir of singers with different voice ranges, or in an ensemble with instrumentalists, such as a rock group or baroque ensemble. As in many respects human song is a form of sustained speech, nearly anyone able to speak can also sing. Singing can be formal or informal, arranged or improvised. It may be done for pleasure, comfort, ritual, education, or profit. Excellence in singing requires time, dedication, instruction, and regular practice. Professional singers usually build their careers around one specific musical genre, such as classical or rock. They typically take voice training provided by voice teachers or vocal coaches throughout their careers.

Onika Tanya Maraj (born December 8, 1982), known by her stage name Nicki Minaj ( /mɪˈnɑːʒ/), is a Trinidadian-born American rapper and singer-songwriter. She was born in Saint James, Trinidad and Tobago and when she was 5 years of age she moved to the New York City borough of Queens, where she grew up.

After releasing three mixtapes between 2007 and 2009 and being signed to Young Money Entertainment in August 2009, Minaj released her debut album, Pink Friday, in November 2010. It quickly became a commercial success, peaking at number one on the U.S. Billboard 200 and being certified Platinum by the Recording Industry Association of America (RIAA) a month after its release. She became the first female solo artist to have seven singles on the Billboard Hot 100 at the same time. Her second single, "Your Love", reached number 1 on the Billboard Hot Rap Songs chart, making Minaj the first female artist to top the chart unaccompanied since 2002. She also became the first female artist to be included on MTV's Annual Hottest MC List. Minaj was named the 2011 Rising Star by Billboard. Her second studio album, Pink Friday: Roman Reloaded was released on April 3, 2012.

Robert John Downey Jr. (born April 4, 1965) is an American actor who made his screen debut in 1970 at the age of five, appearing in his father's film Pound, and has worked consistently in film and television ever since. During the 1980s, he had roles in series such as coming of age films associated with the Brat Pack. His role in Less Than Zero (1987) was the first time Downey's acting would be commended by critics. After Zero, Downey was cast in starring roles in bigger films, such as Air America (1990), Soapdish (1991), and Natural Born Killers (1994). He played Charlie Chaplin in the 1992 film Chaplin, for which he received an Academy Award nomination for Best Actor.

Between 1996 and 2001, Downey was frequently arrested on drug-related charges. After being released from the California Substance Abuse Treatment Facility and State Prison in 2000, Downey joined the cast of the hit television series Ally McBeal playing the new love interest of Calista Flockhart's title character. His performance was praised and received accolades, but his character was written out when Downey was fired after two drug arrests in late 2000 and early 2001. After one last stay in a court-ordered drug treatment program, Downey finally achieved lasting sobriety and his career began to take off again. He appeared in semi-independent films such as The Singing Detective (2003), Kiss Kiss Bang Bang (2005), and A Scanner Darkly (2006). He also had supporting roles in the mainstream films Gothika (2003) and Zodiac (2007). In 2004, Downey released his debut studio album The Futurist.

Jordin Brianna Sparks (born December 22, 1989) is an American pop / R&B recording artist, songwriter and actress who rose to fame as the winner of the sixth season of American Idol. She hails from Glendale, Arizona. Sparks won when she was 17 years old, making her the youngest winner in Idol history and remains the last female to win American Idol. She followed her American Idol victory with the release of her self-titled debut album in 2007, which has gone platinum in the U.S. and has sold over 2 million copies worldwide. Sparks' single, "No Air" is the highest-selling single by any American Idol contestant, selling over 3 million digital copies in the U.S. and Canada. Due to the success of her debut album and its four top 20 singles, she has received numerous awards and nominations including an American Music Award in 2008 and her first Grammy nomination in 2009. In 2009, Billboard magazine's 91st-best-selling music artist of the 2000–2009 decade.

Michael Steven Bublé ( /ˈbuːbleɪ/; born 9 September 1975) is an Italian Canadian singer and actor. He has won several awards, including three Grammy Awards and multiple Juno Awards. His first album reached the top ten in Canada and the UK. He found a worldwide audience with his 2005 album It's Time, and his 2007 album Call Me Irresponsible which reached number one on the Canadian Albums Chart, the U.K. Albums Chart, the U.S. Billboard 200 albums chart, the Australian ARIA Albums Chart and several European charts. Bublé has sold more than 30 million albums worldwide.

Michael Bublé was born in the City of Burnaby, British Columbia, Canada to Lewis Bublé, a salmon fisherman, and Amber (née Santagà). He has two younger sisters, Crystal (an actress) and Brandee. He attended Seaforth Elementary School and Cariboo Hill Secondary School. According to an Oprah interview on 9 October 2009, Bublé dreamed of becoming a famous singer since age two. When he was a teenager, he slept with his Bible and prayed to become a singer. Bublé's interest in jazz music began around age five when his family played Bing Crosby's White Christmas album at Christmas time. The first time that his family noticed his singing talent was at Christmas time when Bublé was 13 years old, and they heard him powerfully sing the phrase "May your days be merry and bright" when the family was singing to the song "White Christmas" in a car ride.