Kate Hudson has revealed she and her boyfriend Danny Fujikawa are expecting their first child together - and it's a baby girl.

The 38-year-old actress shared the news on her Instagram account in a clip showing the duo and Hudson’s sons Bingham Hawn, 6, and Ryder Russell, 14, popping four huge balloons to reveal showers of pink confetti.

The Almost Famous actress said she could no longer hide the news as she was starting to show and she was 'exhausted' from making such a fuss about it.

"SURPRISE!!!" she wrote. "If you've wondered why I've been so absent on my social channels it's because I have never been more sick! It's was the most sick first trimester of all my children.

Boomerangs have made me nauseous, Superzoom is an easy way to have my head in the toilet, food instagrams make me queezy and thinking too much about insta stories made me even more exhausted than I already had been. If you've seen me out and about smiling and pretending like everything is amazing...I was lying!"

"BUT! I have broken through on the other end of that and rediscovering the joys of insta/snap," she continued. "We have been trying to keep this pregnancy under the radar for as long as possible but I'm a poppin now!

"And it's too darn challenging to hide, and frankly hiding is more exhausting then just coming out with it! My kids, Danny, myself and the entire family are crazy excited! A little girl on the way."

"Omg I look like a crazed fan attacking you in this video!!!!!" commented Hudson's friend Sara Foster, who is also Fujikawa's stepsister. "I'm so excited!!!! Finally a girl!!!!!!"

Hudson and Fujikawa have been dating for more than a year.