Watch as Coldplay's Chris Martin stops off at pub and plays piano for lucky drinkers

Chris Parkin, 47, described "the most surreal five minutes ever" as the star and his girlfriend, actress Dakota Johnson, visited The Stag Inn in Hinton Charterhouse late on Sunday afternoon.

The singer-songwriter hopped onto the piano after a couple at the pub, currently planning their wedding, mentioned their first song will be Coldplay's A Sky Full of Stars.

"He just said, 'Well, do you want me to play it?' It was really brilliant, a brilliant moment," Mr Parkin told the PA news agency.

"It's always a little bit of a shock, things like that.

"It was one of those things where you go, 'Right, this is happening'."

In a video posted to the pub's Twitter account, the star asks the couple their names before playing his band's hit song to the room.

"You never know who might pop in for a pint!" the account wrote.

Mr Parkin described the moment earlier on when Martin walked into his pub alongside Johnson - the daughter of Hollywood stars Melanie Griffith and Don Johnson - whom he did not recognise.

"I said, 'He looks a bit like Chris Martin'," he said.

"And his PA said 'Yes, that is Chris Martin'."