He tells Austin 360: "When she left, we took a little bit of time off and then went in the studio to make an album back in 2003. And we've done a number of successful tours, business wise and I'd say artistically as a four-piece.

"The only difference, really, is that Stevie Nicks is sort of at one end of the spectrum. She's representing one pole, I'm representing the other end of that, and Christine is somewhere in the middle.