Katheryn Elizabeth Hudson known professionally as Katy Perry, is an American singer and songwriter. After singing in church during her childhood, she pursued a career in gospel music as a teenager. Perry signed with Red Hill Records and released her debut studio album Katy Hudson under her birth name in 2001, which was commercially unsuccessful. She moved to Los Angeles the following year to venture into secular music after Red Hill ceased operations where she subsequently began working with producers Glen Ballard, Dr. Luke, and Max Martin. After adopting the stage name Katy Perry and being dropped by The Island Def Jam Music Group and Columbia Records, she signed a recording contract with Capitol Records in April 2007.
Justin Drew Bieber is a Canadian singer and songwriter. After a talent manager discovered him through his YouTube videos covering songs in 2007 and signed to RBMG, Bieber released his debut EP, My World, in late 2009. It was certified platinum in the U.S. He became the first artist to have seven songs from a debut record chart on the Billboard Hot 100. Bieber released his first full-length studio album, My World 2.0, in 2010. It debuted at or near number one in several countries and was certified triple platinum in the U.S. It was preceded by his most successful single to date, "Baby".
1- Katy perry