Pixie tamed her perky assets in place with the skimpy number which she complemented with a matching cropped shirt.
Embracing her natural features with barely-there make-up, the Cry Me Out singer allowed her blonde curls to flow effortlessly behind her as she cosied up to her model beau.
The Select Model Management signed star, 28, flaunted his muscular physique by ditching his top to enjoy the beachy surroundings.
The pair - who had been dating for six years before Oliver got down on one knee to propose in London nearly two weeks ago - went on to enjoy a scenic bamboo rafting trip.
Chilling: The pair - who had been dating for six years before Oliver got down on one knee to propose in London - went on to enjoy a scenic bamboo rafting trip later on in the day
Pixie, who's Breakfast At Tiffany's stage run came to an end in September, added a touch of glamour to the low-key activity.
Perched at the edge of the raft, she cheekily glanced over her shoulder while Oliver captured the moment on camera.
Earlier on in the trip, Pixie flaunted her sparkler as she showed off her incredible figure in a plunging emerald green swimsuit and matching striped oversized frames by Dolce and Gabbana.
She wore her hair in natural curls as she perched on the end of a boat looking out at the sunset.
Having the time of her life: Earlier on in the trip, Pixie flaunted her sparkler as she showed off her incredible figure in a plunging green swimsuit and matching striped oversized frames
Sexy: The blonde bombshell also wore a leopard print halter number and trendy frames while on her trip
She captioned the image with the words: 'hammock in the sea eee we love you water villa red sky at night.... @sandals_uk #overwatervillas.'
Nearly two weeks ago, Oliver finally popped the question, proposing to Pixie in the heart of London.
The male model and actress/singer both took to their Instagram accounts to share the happy news after Oliver got down on bended knee in the shadow of St Paul's Cathedral.
Her Marilyn moment: She also wore a stunning halter neck number as she smiled for the camera
Beautiful: This stunning shot was captioned with the words: 'I love listening to the ocean and watching the #OverWaterSuites @Sandals_UK #SandalsRoyalCarribean'
Pixie exclaimed it was the 'biggest surprise ever' as she showed off a dazzling diamond ring, adding simply in the photo's caption: 'so happy.'
The gorgeous blonde also shared a snap of the two kissing at Madison Restaurant & Bar in front of St Paul's as the sun set, with glasses of bubbly in hand, alongside the caption 'ahhhh'.
Oliver meanwhile joked that he'd been 'caught in the act' after a fan spotted the romantic moment, with Pixie seen wiping away tears of joy.
Congratulations! Oliver proposed to girlfriend of six years Pixie two weeks ago
Sealed with a kiss: The lovebirds sipped bubbly and shared a kiss during the romantic moment at London's Madison Restaurant & Bar
Sharing the joy: Pixie exclaimed it was the 'biggest surprise ever' as she showed off a dazzling diamond ring, adding simply in the photo's caption: 'so happy'
Reposting photos of the big moment, Oliver - who began dating Pixie in 2010 - told his fans: 'Caught in the act. She only bloody said yes.'
He later added: 'What a beautiful day and the most beautiful woman in the world said yes to me on it. Lucky man.'
A representative for Pixie told MailOnline on Sunday: 'She's so excited and celebrating with her family - and it was the most wonderful surprise at St Paul's Cathedral this afternoon.'
The lovebirds' engagement comes several months after Pixie complained that she regularly faced questions about when she and Oliver would take their romance to the next level.
Spotted! Meanwhile, Oliver joked that he'd been 'caught in the act' after a fan spotted the romantic moment, with Pixie seen wiping away tears of joy in the pics which he reposted on Instagram
Smitten: He later added: 'What a beautiful day and the most beautiful woman in the world said yes to me on it. Lucky man'
Just can't hide it! A spokesperson for Pixie told MailOnline that the star is 'so excited and celebrating with her family' after her surprise engagement
Cannes Lions: Oliver Cheshire gushes over girlfriend Pixie Lott
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Speaking to Notion magazine last year, she said: 'Honestly, people are obsessed with it! I don't know, I always get asked "when are you getting married?"
'As soon as I started going out with Oliver I was asked it, and I still get asked in it every interview.
'I don't know why that is, maybe it's just something that people want to hear about, I don't know. I think male celebrities probably don't get asked it as much.'
More recently, Pixie gushed about her relationship with handsome Oliver as she revealed the elements that made their romance work.
'I think every relationship is different and there are no real rules,' she told The Sun in March of this year.
'Some of my friends have dated loads of people and others are still with the first person they started going out with, a bit like me. If it feels right, you just go with it.'
Obsession: Last year, Pixie said that people seemed to be 'obsessed' with her getting married
Trust: More recently, Pixie said that her and Oliver's trust for one another has been a fundamental element on the success of their romance
Passion for fashion: Over the years, the stars have become a fixture on the fashion circuit
Pixie Lott and boyfriend Oliver Cheshire looked loved up
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And, despite their hectic schedules - which often see them working thousands of miles apart - the couple have learned the true value in trusting one another.
Pixie added: 'Either I’m away or he’s away, and those times are hard. But we’re used to it because it’s been like that since the beginning.
'We have complete trust, and I think if we didn’t have that, it would be much more difficult than it is. I’d like to think we were heading that way [towards marriage], definitely.'
Pixie recently reunited with her man after some time in Los Angeles, where she celebrated Halloween at Chateau Marmont in West Hollywood last weekend and attending the BAFTA Britannia Awards.
Before jetting to America, the star enjoyed a well-earned holiday in Chania, Crete, with Oliver, after starring in the West End production of Breakfast At Tiffany's.
Pixie appeared in the production as Holly Golightly at the Royal Haymarket Theatre from June to September, but the role has now been taken over by Georgia May Foote.
Ringing in a new era: Earlier this year, Pixie said that she'd 'like to think' that she and Oliver were heading to marriage
Growing together: The photogenic couple, pictured in July 2011, began dating in 2010
