It was an unforgettable stag do.

Norfolk builder Chris Hallam and nine of his close friends were dressed in Bananaman costumes when they bumped into Professor Stephen Hawking in Cambridge.

The 29-year-old groom of Post Office Road, Lingwood, spotted the celebrated academic getting out of his car.

And to his amazement, the Brief History of Time author was happy to pose for souvenir photos.

Father-of-one Mr Hallam is due to marry fiancée Kizzy Davis, 34, on March 29.

And she said it was surreal how far news of the chance encounter has reached.

'It's been a bit crazy how quickly it's spread everywhere,' she said. 'It's bizarre.

'Chris said Professor Hawking was a really good sport.

'He didn't speak but his son spoke on his behalf.

'He said 'How about we ditch our plans for the meal and go out with the lads?'

'He did a big grin.'

And she joked: 'My hen do is this weekend and I'm feeling the pressure to go one better!'