She has previously championed her enviable hourglass curves - and was well known for never missing an opportunity to flaunt them when she first shot to fame.

But Kelly Brook, 38, has confessed that she is desperately trying to lose weight in order to shrink her bust, because she is in 'so much pain' that she's forced into bed by 5pm every evening in order to rest her back.

During an appearance on ITV's Loose Women on Friday, the brunette beauty explained that although she has always had a 'booby' frame, her breasts now weigh about a 'kilogram' each after she grew to a 34FF cup size.

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Candid: 'There about a kilogram each': Kelly Brook confessed she is trying to 'lose weight' off her boobs as she lamented being in 'so much pain' during Friday's Loose Women

'It's about a kilogram each,' Kelly divulged. 'I've gone up quite a lot. I was always booby, but I have gone up quite a lot. I think I've gone up to a 34FF.'

Dressed in a notably more conservative style that her flesh-flashing days, the actress confessed that she decided to lose weight following the advice of a doctor, who said she had put on 'quite a lot' of pounds on her cleavage.

She told Loose Women's panellists: 'I’ve been having lots of back problems recently and I went to the doctor and he said, "I think you might need to lose weight…"

Hourglass curves: Kelly is famed for her ample curves (pictured in October 2017)

Dramatically different: The curvy model, 38, admitted her large breasts (L) now weigh about a 'kilogram' each as she is a 34FF cup size (pictured right in 2003 with a smaller bust)

Barely there: The star, pictured in 2010, became known for her willingness to pose in barely-there ensembles during her modelling days

Flashing the flesh: Her new style is notably more demure than her previous flesh-flashing sartorial displays. She's pictured in 2000

'I was like, really? He was like, "Yeah you know you’ve put on quite a lot of weight, up here (motions to breasts)."

'Because that’s where I put it on, on my boobs. So my bras were not supporting me, it’s completely thrown my back out.'

The Celebrity Juice star added she now is 'laid up in bed' by 5pm in 'so much pain' after exercising to shed the pounds.

Ouch: 'It's about a kilogram each,' Kelly divulged. 'I've gone up quite a lot. I was always booby, but I have gone up quite a lot. I think I've gone up to a 34FF'

Doctors orders: The actress confessed she decided to lose weight following her doctor's advice who said she had put on 'quite a lot' of pounds on her cleavage

Candid: Recalling her time at the doctors, she said: 'I’ve been having lots of back problems recently and I went to the doctor and he said, "I think you might need to lose weight…"'

'I'm in so much pain': The Celebrity Juice star divulged how she has been 'laid up in bed' by 5pm in 'so much pain' after exercising to shed the pounds

She explained: 'So now I’m literally training to try and lose weight off my… so I’m running, but I can’t find sports bras so I’m actually just running holding my breasts to try and keep them in place.

'But it is helping, he says if I strengthen my core it’s going to support me better. 5pm at night I’m just laid up and I’m in so much pain…

'People think that, "Oh I want a boob job, I want boobs…" Because I was born with them I don’t know anything different – I would love to not have boobs and just be able to wear lovely little tops and do more sport and not have back problems and not have to worry about them sagging or whatever they’re going to do at some point.

Try it out: Kelly loaded up Kaye Adams' bra with tins of beans to the equivalent weight of her one kilogram breasts so that the Scottish presenter could see how it felt

Strapped in: Kaye wore the loaded bra as she chatted with the panel on Friday's show

Jog on: Kaye then attempted to run with the weighted bra so she could experience the discomfort that Kelly does when she has to do cardio

'I think it’s the equivalent of three basketballs or something…. It’s really sore, sciatica. It is excruciating. Hopefully I’ll fix it.'

Whilst Kelly may have been lamenting her new shape, romantically she is as happy as can be with her boyfriend, Jeremy Parisi.

The couple have been blissfully happy together since sparks flew when they first started dating in April 2015, and in November, the beauty divulged she would love to get married at the Savoy - despite the pair not being engaged.

When asked on Loose Women if she is now betrothed, Kelly responded: 'I'm not engaged, no. But I would love to marry my boyfriend. I'm waiting for him to ask me.'

Wow: The star previously served as the face and body of Ultimo lingerie. She's pictured in 2010

Cute couple: Whilst Kelly may have been lamenting her new shape, romantically she is as happy as can be with her boyfriend, Jeremy Parisi

Making note of the sparkler on her ring finger, she quipped: 'It doesn't fit on any other finger, because they're all too fat!'

She continued: '[Jeremy] gave me the ring when we were six months into dating. I was like, "Are you proposing?" He was like, "No!" He was like. "You always get engaged, but you never get married!" I think he wants me to ask him, actually.'

As well as jetting off to France, the pair often spend time together at Kelly's £1million country pile in Kent which boasts of a 600-year-old apple farm where she grows her own vegetables.

Kelly also took part in a game of I Have Never with Olly Murs during her appearance on Loose Women, where both stars revealed to having sex in a 'public place'.

She, Olly and Linda Robson all held up their 'I Have' paddle, as host Christine asked whether they had done so. Left red-faced, Olly insisted: 'It was before I was famous!'

Cheeky: Kelly also took part in a game of I Have Never with Olly Murs during her appearance on Loose Women, where both stars revealed to having sex in a 'public place'

Good sport: Kelly didn't hold back when it came to answering the revealing statements