A day after going public with his new love for the first time Paul McCartney appeared to be heading back the Psychedelic era as he was pictured in London with a multi-coloured floral shirt.

The 65-year-old looked to have raided his seventies wardrobe as he stepped out in the flamboyant ensemble which was matched with sunglasses and jeans.

The solo outing follows the former Beatle's public appearance with girlfriend Nancy Shevell just two weeks after his six year marriage to Heather Mills was officially ended.

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Hippy throwback: Paul harks back to his flower power days in a floral shirt while out and about in London today

As Miss Mills sunned herself in the Canary Islands, the former Beatle took the multi-millionaire heiress and socialite to a ceremony at one of America's top universities where he was awarded an honorary doctorate in music.

Sir Paul looked relaxed as he attended the service with Miss Shevell, 47, who was wearing a low-key floral summer dress.

The singer changed from his suit into the traditional black graduation robes and mortarboard hat before collecting the accolade in front of a crowd of thousands of cheering students at Yale University.

The institution's president Richard Levin told Sir Paul as he presented the award: 'You have played every chord, touched every emotion – here, there and everywhere.

'You have pushed the boundaries of the familiar to create new classics.'

Publicity-shy Miss Shevell kept a little distance behind the star as they arrived.

Official? Sir Paul McCartney and his new girlfriend Nancy Shevell attend a ceremony at Yale University in Connecticut

However, her decision to escort to him to the event will further fuel rumours that their love affair is becoming increasingly serious.

The couple were first pictured in a passionate embrace in the front of his car last November.

They were spotted again last month frolicking in the sea and enjoying romantic walks on the beach whilst on holiday together in the Caribbean.

Sir Paul has also been linked to actress Rosanna Arquette after the pair were seen enjoying a string of dates but this is understood to have fizzled out.

He was also reported to have become close to former Olympic horserider Tanya Larrigan.

Miss Shevell is vice-president of her family's £250million transport firm.

She and estranged husband Bruce Blakeman first became friends with Sir Paul and first wife Linda during the early 1990s.

A breast cancer survivor, she has raised hundred of thousands of pounds for charity.

Her family background, elegance and demeanour have already led to comparisons with Linda.

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Accolade: The former Beatle received an honorary doctorate from Yale University for his contribution to the music industry

These latest pictures of Sir Paul with Miss Shevell will no doubt infuriate Miss Mills, who was awarded £24.3million in the divorce settlement.

As her ex-husband paraded his new consort, she was on a relaxing break in Tenerife where she was spotted listening to her iPod and surfing the net on her laptop.

In a bitter outburst on GMTV earlier this year when she discovered he was dating she said: 'I think he's got three different girlfriends, so I wish all the girls the best of luck. Better them than me.'

Sir Paul met Miss Mills, 40, at a charity event in 1999 just a year after Linda died from breast cancer.

Despite his children's serious misgivings about his new beau, he wed the former model in 2002 at the17th century Castle Leslie in County Monaghan, Ireland.

The couple had daughter Beatrice a year later but announced their separation in 2006 initially blaming press intrusion.

However relations between the two camps rapidly deteriorated during the divorce.

Earlier this month a judge took just 30 seconds to end the marriage.

A spokesperson for Sir Paul declined to comment on his relationship with Miss Shevell.