September 2013, and Stevie Nicks is about to perform Landslide at the O2 in London, where Fleetwood Mac are playing three nights. Before she does, though, she has a dedication to make. "This is for my mentor. Big sister. Best friend," she says, and there are precious few people in the venue who don't know she's talking about Christine McVie, her fellow female bandmate and the Mac's keyboard player, as well as one of its singers and songwriters from 1970 until she quit in 1998.

It is not the first time Nicks has talked about McVie. In 2009, she told the audience at Wembley Arena that she thought about her "every day". Earlier this year she admitted to the Observer: "I'd beg, borrow and scrape together $5m and giveit to her in cash if she would come back. That's how much I miss her!"

This time, though, was different. When it came to the end of the band's set, McVie stepped onstage with them for the first time in 15 years to run through Don't Stop, her enduring anthem about staying positive in the aftermath of a breakup.

"It was like falling off a bike," McVie says when I meet her in her south London apartment, a beautiful space situated so close to the banks of the Thames that it feels as if we're floating above it. "I climbed back on there again and there they all were, the same old faces!"

Was she nervous?

"Not as much as I thought, because none of the band drink any more and