The News of the World says that the Fightstar singer has rejected a deal to join ex-band members James Bourne and Matt Willis on tour, despite a £1 million offer from promoters.
A source close to Simpson told the newspaper: "He hates being associated with Busted. He had an unhappy time. He's in Fightstar now and also recording solo tracks."
Busted sold three million albums prior to their split in 2005.