Hailee Steinfeld is pregnant.

The actress announced in her Substack newsletter on Friday (Dec 12) that she and her Buffalo Bills quarterback husband Josh Allen, both 29, are set to welcome their first baby together.

The newsletter listed her 29 favourite moments from the past year as part of her 29th birthday. At the end of the list, the Hawkeye star included a video in which she revealed the joyous news.

Hailee posed in the snow and displayed her bump as Josh kissed her tummy. The smitten couple then smiled and posed together as Hailee donned a fleece that had "mother" emblazoned across it.

At the end of the video, the camera panned out to reveal both standing on either side of a small snowman.

After it was announced in her newsletter, the couple made a joint Instagram post with the same clip, which they captioned with a single red-heart emoji.

NFL legend Josh commented with: "I love you."

It then sparked thousands of congratulatory messages in the post's comments section, including from their celebrity pals.

The Electric State actress Millie Bobby Brown, 21, penned: Oh my god Hails!."