Josh Brolin and wife Kathryn announce they're expecting their first child together

Josh Brolin and his wife Kathryn have announced they're expecting their first child together.

The excited dad-to-be shared the lovely news on his Instagram account on Tuesday, posting a photo of his wife of two years and her growing baby bump alongside a selfie of themselves enjoying a hike.

The actor captioned the snap: ‘There’s a new sheriff in town, and she’s no bigger than a sweet potato. Hang on to your hats. #jbkbstucktogether #lilbeanterritory #loveisaslovedoes’.

Kathryn also confirmed the news on her own Instagram account, sharing a snap of herself gazing adoringly at her growing bump.

Revealing that the soon-to-be parents are expecting a baby girl, she said: ‘Something’s cookin... Baby Girl Brolin on the way #jbkbstucktogether #loveisaslovedoes’.

This will be the couple’s first child together, although Josh is already a dad to daughter Eden Brolin, 24, and son Trevor Brolin, 29, with ex-wife Alice Adair.

He was also previously married to actress Diane Lane, from 2004 until 2013, but they had no children together.

Josh and Kathryn's pregnancy announcement comes just two years after the couple tied the knot in North Carolina in 2016.

Discussing their wedding plans at the time, Josh told E! News: ‘I'm the guy who has to force himself to back off! I'm such a control freak and I want to control everything.

‘It's not even that I want to control it — I just want to be in the middle of it,’ he continued. ‘I want to be in the nucleus of it because that's the fun part. That's the nectar.’

Last year, the Avengers actor raved about married life with Kathryn, telling US Weekly: ‘Oh, everything is good. When it’s good, it’s good... The best thing is I don’t understand when people don’t want to be around their wives. That’s the best thing, because I don’t really care to understand that.'