In the snap Tina's large bump is covered with a pretty red and white polka dot dress and she also reveals her fun flamingo phone cover. The mum-to-be captioned the picture, 'Ready to drop!!!! #BigMama #AnyDayNow!!! 💋❤️'
Fans were quick to speculate as to whether or not Tina was expecting twins, or just a very large baby, judging by the size of her tummy. One Twitter user, Dee Ann, said 'damn 😱😁😍 do you want twins or just one? Lol we can't wait to see 👶🏻❤️' while David on Twitter said, 'looks like u having twins ha xx'. Micky M commented, 'The kid will be 8 lbs., 6 ounces. #placingmybet.
Tina announced the lovely news that she was expecting a baby with boyfriend Paul Cashmore just two months ago!
The star was six months into her pregnancy and is due in June, she revealed to OK! magazine at the time.
The 39 year old said in the interview that they didn't have any trouble conceiving: 'I have friends who've tried for years to get pregnant but we conceived within three months of trying.
'I know it sounds silly but it did take us by surprise - we thought it would take longer.'
The couple will welcome their first child in June
Tina and Paul have found out the gender of their baby, but they're keeping it a secret for now.
'When the nurse told us what we were having I burst into tears. I didn't mind if we had a girl or a boy but I was so overcome with emotion that I couldn't help myself', the singer said.
'Being able to put a gender to what was growing inside me suddenly made it feel very real.'
The couple have been together for three years, after meeting back in 2012 on the set of Russell Grant's charity music video for The Clapping Song.
'Until Paul I hadn't really met a man I wanted to have children with', Tina says. 'I'm 40 this year so there was a part of me that was worried I might have left it too late, but thankfully that wasn't the case.'
Talking about marriage, which they do 'all the time', Paul said they almost eloped to Las Vegas, but their plans have changed now that they're becoming parents.
'Before Tina got pregnant we were considering flying to Las Vegas to tie the knot, just the two of us', Paul said.
'Things have changed now we're having a baby - we'd want him or her to be there, so I imagine we'll do something a bit bigger when the time comes', the mum-to-be added.
However, when the time comes for the two to get married, Paul still wants to surprise his other half: 'I want to take Tina by surprise. She knows it's coming, though. I'd like us to be married within a year of the baby being born.'
Tina was part of the band S Club 7
She's also shared the happy news with her former bandmates, who she says are really happy for her, especially fellow mums Rachel Stevens and Jo O'Meara.
The Bring It All Back singer said: 'Jo burst into tears. She's so sweet, she couldn't have been happier for us.'
And the expecting mum has already started planning her little one's future: 'I'd love my child to be friends with Jo and Rachel's children. Perhaps we could encourage them to start their own band, that would be cute!' Awww!
Full interview with Tina Barrett from OK!