STEVIE NICKS has said Britney Spears has not worked hard enough to be famous.
The Fleetwood Mac singer said Britney had gained instant fame without putting in the hard graft.
She said: "You have to pay your dues to be a real rock star.
It's different in that Britney did not join a band when she was 18 and practice every day for five hours Monday through Friday and then play gigs Friday, Saturday and Sunday."
Fleetwood Mac are rumoured to be on the bill for this year's Glastonbury Festival as part of their Fleetwood Mac Unleashed: Hits Tour 2009.