Keith Richards has opened up about the state of his relationship with bandmate and songwriting partner Mick Jagger after upsetting the Rolling Stones frontman with revelations in his bestselling memoir.

The guitarist poked fun at the size of the singer's manhood and took aim at him over his womanising ways, among other things, in the tome Life - and had to apologise to Jagger before the group could make plans for a 50th anniversary reunion tour last year (12).

Filmmaker Brett Morgen recently told Wenn he was a party to the tensions between Richards and Jagger as he recorded interviews for his Crossfire Hurricane documentary, but insists things had started to "thaw" by the time he wrapped the movie.

Both rockers have acknowledged the feud Richards' revelations caused, with Jagger telling Rolling Stone magazine that an apology from his bandmate was a "prerequisite" for the band's 2012 reunion, which led to the ongoing 50 & Counting tour, and now the guitarist has spoken at length about the pair's current relationship.

He tells Men's Journal magazine, "(It's) smooth. Even. Definitely workable. Otherwise, we wouldn't be doing it. A lot of these things are blown way out of whack... It's like two very volatile brothers - when they clash, they really clash, but when it's over, it's over because we both know we need each other; we both enjoy working with each other.

"Ninety per cent of the time it's as cool as it can be, then, of course, the people only get to hear about the 10 (per cent). And the 10 are pretty fierce.

"It took him (Jagger) a while to come around... demanding apologies and all of this c**p. I'd say, 'Eh, I'm sorry I upset you'."

But Richards insists the fall-out from the feud won't prevent him and his songwriting partner coming together in the studio if they choose to record new material: "We could do that. It's not that we would seek each other out for fun or company... but we could definitely sit down and go, 'Let's go in the back room... I've got this song'.

"I've always found working with Mick is like a joy, it's a real pleasure. It's outside of the realm of work is where we tend to disagree."