Coldplay star Chris Martin had to apologise to fans at a concert in Boston, Massachusetts on Sunday after making a mistake in the opening lyrics of their song Warning Sign.

It is the second time in a month that the British rocker fluffed the words of the heartache track - he previously messed up the same part of the show while performing in Washington, D.C. in early July.

Only this time he jokingly blamed the mishap on the London Olympics.

He told the audience, "I was thinking about the Olympics. I was distracted. I was not in the break-up frame of mind I needed to be in (for the song). I'm gonna get back into it; I'm gonna stop thinking about pole vaulting and things like that.

"It's a big deal. You can't blame a guy for thinking about it every once in a while... but the best concert in the world is happening right here, right now. F**k the Olympics. Let's have a f**king great time in Boston."

Realising the power of social networking sites like Twitter.com, Martin then added, "Please don't tweet that I said 'F**k the Olympics'... I'll never hear the end of it!" (MT/WNWE/MJ)