Rachel Riley once performed one of her 'Strictly Come Dancing' routines for Stephen Hawking.

Rachel Riley

Rachel Riley

The 'Countdown' star has revealed that the surreal incident took place during a night out with her showbiz pal Jimmy Carr and her boyfriend - and 'Strictly' professional partner - Pasha Kovalev.

Rachel recalled: "I was filming 'The Gadget Show'. So in the morning Ainsley Harriott cooked me three Christmas dinners - in October - and then Jimmy Carr messaged saying he was going out with Stephen Hawking and his family and friends, who are good mates.

"His carers and family are big 'Strictly' fans and I was on 'Strictly' at the time, so I hotfooted it down from Birmingham - I was mid-training - and I took Pasha with me. And then you know what Jimmy's like, so he just said, 'Go on, give us a show.'"

But Rachel, 32, admitted that her performance didn't exactly go to plan.

Appearing on 'The Chris Ramsey Show', she said: "He put the music on. I went to do the dance, and three beats in I accidentally head-butted Pasha. We have it on video somewhere."

Meanwhile, Rachel revealed last year that she doesn't want to get married to Pasha.

The mathematician admitted she has no desire to settle down with the hunk as they're happy with the way things are going.

She said: "I am in love now. I don't feel I have to get married. I don't think I need that pressure any more.

"I don't worry about getting married or whether he is taking a long time in the morning or whether he has done the dishes. That does not really bother me in the long term. I feel settled."