Rachel, a mum of two, showed off her incredibly toned figure as she contorted her body for the complicated handstand move.
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Rachel Hunter: "Little fun in the sun in London"
Wearing just a black string bikini, the body-confident New Zealand model captioned the photograph "Little fun in the sun in London."
Rachel, who was previously married to Rod Stewart, is based in LA and is regularly pictured going to pilates classes there. She has also been a big fan of bikram yoga for seven years.
But true happiness, she says, doesn't come from external beauty.
Rachel Hunter pictured at the Serpentine Gallery's Summer Party this week
"It's my job to look good – but I've always been a believer that real beauty comes from within," she recently said in an interview with New Zealand Woman's Weekly.
"But I definitely look in the mirror and think, 'That could be better.' You let things go a bit more when you're older, don't you? I don't like my jowls – there are always things that can be worked on. And it's a hard decision as to what age you stop wearing a bikini.
"My advice to anyone over 40 is to only do it if it makes you feel good," added the star, mum to Renee, 21, and Liam, 19. "And don't go out in midday sun – the lighting is terrible! Stay under the umbrella between 11am and 2pm. And hey, if I was 20lb overweight, do you think I would be jumping into a bikini on a photoshoot? Hell, no!"
Rachel Hunter was married to Rod Stewart from 1990 until 1999. They have two children together, Renee and Liam
She added, "I always want to tell girls who are obsessed with their weight that happiness doesn’t come from being skinny."
"It's not that time when you're wearing jeans that you think make you look good, or when you are standing up straighter in those new heels that define sexiness. It's simply when you're exuding inner confidence and feel at peace. When that moment happens, remember it. Being sexy is an internal feeling."