After the ordeal he went through with Heather Mills, it is something of a surprise to find Paul McCartney down on one knee in front of another girl.

But while the word is that their relationship is flourishing, for now at least he was merely taking a holiday snap of Nancy Shevell.

The couple were taking a stroll in the popular tourist town of Sante Fe, New Mexico, stopping off there during a month-long road trip across seven US states. 

Picture perfect: Sir Paul McCarthy on holiday with heiress girlfriend Nancy Shevell

The former Beatle recently went through a very public split with ex-wife Heather Mills

Sir Paul, 66, and his 47-year-old heiress girlfriend are fulfilling the star's lifelong dream to travel along Route 66 in an old Ford Bronco truck.

The couple joined the route in Illinois last Saturday and are following it all the way to Santa Monica pier in Los Angeles. 

It is understood they have been camping out under the stars rather than heading for the nearest five-star hotel.

Fellow campers said they seemed 'totally in love'.

One added: 'It was incredible to see one of the world's richest musicians going back to basics.

'They didn't seem to have a care in the world.'

The month-long road trip is believed to be the couple's longest holiday - they previously vacationed together in the Caribbean in April.

A source said: 'The road trip was Nancy's idea as a way of them getting to bond and spend time together - just the two of them.'

While Sir Paul may not be about to propose marriage, insiders claim that if the holiday goes well, the couple could move in together.

American millionairre Nancy Shevell is on holiday with Sir Paul