Reese Witherspoon flashes her cleavage in a daring low-cut swimsuit as she relaxes poolside in Mexico ahead of 40th birthday

It's hard to believe that Reese Witherspoon will be celebrating her 40th birthday later this month.

The actress looked fantastic on Wednesday as she showed off her petite figure while soaking up the sun with a group of girlfriends in Cabo San Lucas, Mexico.

Reese stripped down to a black swimsuit with a plunging neckline, flashing her ample cleavage and leaving her slim legs on show.

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Reese's one-piece: Witherspoon stripped to a plunging black swimsuit in Cabo San Lucas, Mexico on Wednesday

The 39-year-old protected her porcelain skin from the sun with a large straw hat and a pair of sunglasses over her make-up free face.

Reese, who had been sporting a pair of pink shorts, tied her bright blonde hair into a fuss-free ponytail.

She was spotted lounging around in the sunshine before taking a dip in the pool to cool off, emerging with wet hair as she dried herself with a towel.

Reese made sure to stay hydrated in the heat and was spotted sipping from a bottle of water.

Just peachy: The actress showcased her fantastic figure in the swimwear as she relaxed poolside with friends

A wise idea: Reese wore a large straw sunhat and a pair of sunglasses, and made sure to stay hydrated

Take the plunge in Reese's Ted Baker swimsuit

$129

Ted Baker London 'Ralinda' swimsuit

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We do love it when A-listers shop on the high street.

A matter of days after walking the red carpet at the Oscars wearing a custom made and very dreamy Oscar de la Renta gown, Reese Witherspoon was pictured soaking up some sun in Mexico wearing a one-piece from none other than Ted Baker!

When it comes to swimwear, you can try all trends you want (and believe us, we have!), but sometimes it pays to go back to black.

We love the daringly deep plunge neckline on this swimsuit, as well as the cut outs (watch out for tan lines!) and adjustable halterneck. Click the link (right) to buy it at Nordstrom, but do it quick - we can see this selling out soon!

Whether you're counting down the days until you fly, or are still at the surfing the net stage of booking your holiday, now is the time to invest in some new swimwear. And if you're hungry for more, we've picked out the best of the rest in the edit below.

* PRICES MAY NOT BE AS ADVERTISED

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• $31

  

  Asos Tall plunge swimsuit

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• $40

  

  Topshop plunge mesh swimsuit

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• $119

  

  La Blanca swimsuit at Nordstrom

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• $162

  

  Miraclesuit swimsuit at Nordstrom

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The previous day, the Legally Blonde star had worn a red one-piece with a daring cut-out neckline.

Reese jetted to Mexico after attending the Academy Awards in Hollywood on Sunday, where she was a presenter. 

Not seen was the Oscar winner's three children or her husband Jim Toth, who she will celebrate her fifth wedding anniversary with later this month.

Cooling off: The 39-year-old. who wore her hair in a ponytail, took a dip in the water after soaking up the sun

How does she do it?: It's hard to believe that Reese will be celebrating her 40th birthday later this month

Reese is mom to three-year-old Tennessee with the CAA agent, and also has daughter Ava, 16, and son Deacon, 12, from her marriage to Ryan Phillippe.

The former couple, who starred in Cruel Intentions together, married in June 1999 and split in October 2006, finalising their divorce the following year.

Reese will not be returning as Annette Hargrove in the upcoming Cruel Intentions TV reboot, although her co-star Sarah Michelle Gellar will be back.

Move over Pammie: The star looked like she had stepped off the set of Baywatch in an eye-popping red swimsuit the previous day

It was announced on Tuesday that Kate Levering, 37, is taking on Reese's role, as the mother of lead character Bash Casey, whose father was the late Sebastian Valmont (Phillippe).

The series picks up 15 years after the conclusion of the film, with Bash (Taylor John Smith) discovering his late father's legacy in a hidden journal, and being introduced to a world of sex, money, power and corruption.

Meanwhile Kathryn Merteuil (Gellar) is fighting for control of Sebastian's company, Valmont International.

Holiday spirits: The star laughed and chatted with some pals over drinks in the sunshine

Baywatching: The actress showed a lot of cleavage as she kicked back in Cabo San Lucas

Stunning: The 39-year-old looked incredible youthful as she ditched the makeup and topped up her tan 

Fab figure: Reese was full of body confidence in her racy one-piece

Although fans will be sad that Reese is not appearing on the show, the actress has plenty to keep her busy.

As well as working on her Draper James clothing line, Reese is producing an ABC pilot about a 'ruthless divorce attorney' in Dallas, which will star Grey's Anatomy's T.R. Knight.

She is also set to star in Paul Feig's Wish List, about a woman in her thirties whose life takes a turn when a coin she threw into a magic fountain as a child reaches the bottom.

Reese will additionally appear opposite Matt Damon, Jason Sudeikis, Alec Baldwin and Neil Patrick Harris in 2017 social satire Downsizing, and voices a character in upcoming animated movie Sing.

Jet set star: Reese headed to Mexico after attending the Academy Awards on Sunday, where she presented