20. The Vamps: 21 Under 21 (2014)
Birthdates: Brad Simpson: July 28, 1995 (Age: 19), James McVey: April 30, 1994 (Age: 20); Connor Ball: March 15, 1996 (Age: 18); Tristan Evans: Aug. 15, 1994 (Age: 20)
Last Year's Rank: N/A
Why They're Hot: After signing to Mercury Records in November 2012, the British quartet has risen rapidly over the last year. The Vamps dropped their debut single, "Can We Dance," in September 2013, and followed that up with tunes "Wild Heart" and "Last Night." Meet The Vamps dropped in April 2014 and the album's latest single, "Oh Cecilia (Breaking My Heart)" features fellow Billboard 21-Under-21 honoree Shawn Mendes. Their song "Hurricane" will be featured in the upcoming film Alexander and the Terrible, Horrible, No Good Very Bad Day. As for life on the road, the band has already opened for Austin Mahone and Taylor Swift, and they've got a U.K. arena tour planned for 2015.
Billboard's 2014 21 Under 21 List