Smith has revealed his girlfriend is pregnant with their first child.

Sharing the happy news via Instagram, Smith, who confirmed he was dating Bree in October (17), writes: "I have some wonderful and surprising news - Stormi and I are having a baby!

"It's crazy to see how my life has been so blessed. I'm so happy and can't wait to experience this amazing journey!"

The baby news comes as the 18-year-old and his model sisters prepare to front the new H&M Loves Coachella campaign.

Lucky and the girls have been plucked by the Swedish high street retailer to star in a video to promote its Coachella collection, full of festival gear. It drops in the U.S. on 23 March (17), two weeks ahead of the start of this year's (17) Coachella festival in California.