The ex-I'm a Celebrity and Snog, Marry, Avoid star posted the images of her pregnant body to reassure fans after "a little scare" with her unborn twin daughters.
"Been to the Drs & all super ok!! Thank you Angels x #gettingbiggerbytheminute," she tweeted.
After supportive fans got in touch, Frost added: "Thanks for all your super sweet messages.......you lot really know how to make a big lass feel good!! Sweet dreams x".
Frost also wrote in her NHS pregnancy blog that she is "rather worried" by the possibility of having a twin Caesarean section.
"With a C-section, it's going to be (God willing) so fast that it's sort of 'ok, here's one baby', and then BOOSH!, a minute later, 'here's another!'," she said. "I honestly think I may pass out with the shock."
She later admitted to having a "severe belly button phobia" and said the sight of her new 'outie' "makes [her] feel really nauseous".
"As you can imagine, I can't touch it myself - let alone anyone else," she commented. "But when you're pregnant, people think it's ok to rub your tummy. It's not!
"I am not a buddha. Rubbing my tummy will not bring you good luck. In fact, possibly the opposite - if I lash out and give you a black eye by accident because you've touched my belly button."
Jenny Frost in Atomic Kitten
Frost married the twins' father, Spanish scuba-diving school owner Vicente Juan Spiteri, in 2011.
She has a 5-year-old son Caspar with her ex-partner Dominic Thrupp, to whom she was once engaged.
Frost's former Atomic Kitten bandmates Natasha Hamilton and Liz McClarnon this week teamed up with original member Kerry Katona for ITV2's Big Reunion, which also saw the reformation of pop favourites Liberty X, B*Witched, 5ive and 911.
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