Kate Hudson's half-brother Wyatt Russell is to be a father for the first time.

Kate Hudson kissing Meredith Hagner's baby bump (c) Instagram/KateHudson

Kate Hudson kissing Meredith Hagner's baby bump (c) Instagram/KateHudson

The 41-year-old actress is "over the moon" at the prospect of becoming an auntie again, following the news that Wyatt - whose parents are Kurt Russell and Goldie Hawn - and his wife Meredith Hagner are expecting their first child together.

Kate wrote on Instagram: "Celebrating our next family member today. First for my bro Wy and @merediththeweasel We are over the moon and can’t wait!!!! (sic)"

The 'How to Lose a Guy in 10 Days' actress shared a picture of herself planting a kiss on Meredith's baby bump.

In the background of the photo were balloons spelling out "Baby".

Several stars took to Instagram to congratulate '22 Jump Street' actor Wyatt and 'Strangers' actress Meredith, including Amy Schumer.

She wrote: "Ahhhhhhhh (sic)"

Wyatt is an uncle to Kate's three kids, Ryder, 16, Bingham, nine, and two-year-old daughter Rani.

And Kate and Wyatt are auntie and uncle to their brother Oliver Hudson's sons Wilder, 13, Bohdi, 10, and seven-year-old daughter Rio.

Wyatt previously admitted he tries to spend as much "quality time" with his nieces and nephews as he can.

He said: "We get to go on vacations and stuff in the summer and be able to see each other and hang out. It’s nice.

"It’s funny - from 35 to 37 nothing changes but the 12 to 14 year olds, a lot changes so you want to be there as much as possible. I just try to spend as much quality time with them as I can."

Wyatt and Meredith met on the set of 2016 comedy movie 'Folk Hero & Funny Guy'.