Queen�s Brian May has snubbed a planned duet with Joss Stone so he can do his homework instead.

The pair had been in talks over a special performance for Stone�s appearance at the Concert For Diana Diana at Wembley Stadium tomorrow night, but the guitarist has now pulled out.

His spokesperson Phil Symes explains, �He was never confirmed although they were in discussions about it. Brian is up to his ears trying to complete his PhD thesis so he couldn't do it."