Congratulations are in order for Myleene Klass, who has revealed she is expecting her first child with boyfriend Simon Motson.

Myleene Klass

The TV star made the announcement with an adorable Valentine’s Day Instagram post, posing in her underwear and sporting an already sizeable baby bump.

Sharing the image on Thursday, Myleene simply captioned it with a heart emoji.

Her well-kept secret left her fans scratching their heads at her big reveal.

View this post on Instagram

❤️

A post shared by myleeneklass (@myleeneklass) on

One said, “Hang on????…. wait…, what??? …. congratulations!!! I really hope this pregnancy is easier for you , you brave beautiful mummy xx”

Another asked, “Where did you hide that?” whilst a third added, “I was thinking I hadn’t seen many stories from you lately and now I know why. Congratulations.”

Others were thrilled by the news, rushing to send their congratulations to the mum-to-be.

View this post on Instagram

❤️ #classicbrits

A post shared by myleeneklass (@myleeneklass) on

One gushed, “Beautiful bump.. congratulations. I hope you and baby have a happy, safe and healthy pregnancy & birth xx”

A second said, “Oh my god!!! What wonderful news!!!….congratulations to you both.”

And a third added, “Ahhhh I thought you’d been a bit quiet on social media. Now we know why! huge congratulations to you and your fella.”

Myleene and fashion PR Simon went public with their relationship in May 2017, and between them share four children from previous relationships.

Myleene is already mother to daughters Ava, 11, and Hero, seven, who she shares with her ex-husband Graham Quinn.

While Simon has a son and daughter from his previous marriage.

Myleene gushed over her new romance with Simon earlier this month, telling Fabulous magazine, “How awful that I could have gone through my life and not met him.

“Imagine never getting why people write those crazy love songs or do crazy things.

“I get it now as a grown-up, and it’s a lovely, lovely thing. To feel like this is a whole other level, and it’s quite incredible. I’m just very happy. About time, eh?”