POP! - Serious

from Wikipedia:

Pop! were a UK pop group consisting of Glenn Ball, Hannah Lewis, Jamie Tinkler, and Jade McGuire. The group was formed in the summer of 2003 when they were signed by Pete Waterman.[1] They released three singles on the Sony/BMG record label, but disbanded in early 2005, due to poor record sales.

The group had three hit singles, which all reached the Top 40 in the UK Singles Chart during 2004 and 2005, but each performed under expectations. Their debut single "Heaven and Earth" was withdrawn from the chart because the single contained a track whose length was longer than permitted for that format.[2] Following singles were "Can't Say Goodbye" and "Serious".[3] A fourth single, "Xanadu" (a cover of the Olivia Newton-John and Electric Light Orchestra song), was due to be released but was cancelled when the group split. They had also recorded songs for a planned album. Their single "Heaven and Earth" was licenced for use in Dancing Stage Fusion by Konami in 2005.