The couple stayed in a five-star beachside villa at the Four Seasons Hotel for 10 days – which cost the star £1,000 a night. It comes just five months after he separated from Alex after nearly 20 years of marriage.
An onlooker on the island said: “Despite the age gap there was a lot of laughter and staring into each other’s eyes plus lots of tactile nudges and touches.
“The hotel is very romantic. It’s not the kind of place you would take just a friend. He must be very keen on Summer. Despite looking more like father and daughter, when they did stroll around together they left people in no doubt that they were a couple.
“Summer has clearly put a smile on his face after a difficult time in his personal life.”
The pair spent most of the time enjoying the privacy of their villa, choosing to eat there rather than mix with other couples, but did venture out for a short boat ride.
Paul’s break-up with his wife last year came four years after the couple briefly split following his affair with Marcela Valladolid, a co- star on the US version of the hit amateur baking contest.
The relationship fizzled out after only a few months when Paul confessed he was still in love with his wife. Liverpudlian Paul and Alex, 53,who is also a chef, married in 1998 and they have a son Josh, 16.
They met in 1995, the year Summer was born, and married three years later.
Shortly after her husband’s dalliance with Ms Valladolid Alex said: “In the space of four weeks my life changed irrevocably. One minute I was happily married and the next I wasn’t. It was a complete shock.”
They reconciled a few months after their brief separation in 2013 with Paul later describing the incident as “the biggest mistake of my life”.
Speaking about his marital woes in 2015, he said: “We went through a very difficult time but we’re on top right now.”
Before joining Great British Bake Off in 2010 he worked as head baker at the world famous Cliveden House Hotel and The Dorchester but is now a multi-millionaire whose bread is sold at Harrods and Waitrose.
He previously revealed how his decision to stay with Bake Off after it defected from the BBC to Channel 4 in a £75million deal made him public enemy number one while former hosts Sue Perkins and Mel Giedroyc were mourned.
He said: “I stayed with Bake Off. The girls abandoned it. But I was the one put under siege. I became the most hated man in the country.
“It’s not fun for someone that doesn’t like being in the limelight. Fame brings its own demons.”
Paul’s representatives declined to comment last night.