Julia Stiles is expecting her first child.

The 'Jason Bourne' star and her fiancé Preston J. Cook are due to welcome a baby into the world by the end of the year, her representative has confirmed to People magazine.

It has no doubt been a couple of great years for Julia and Preston as the pair got engaged on Christmas Eve in 2015.

Announcing the news, Julia shared a picture of her hand intertwined with Preston's and the ring could clearly be seen.

She captioned the photo: ''Best Christmas Ever!''

The pair met in 2015 on the set of 'Go With Me' where Preston was working as a cameraman.

Revealing their romance in July, when asked what the best kiss of her life was, she admitted: ''It might have happened this morning. I am dating a camera assistant I met at work called Preston.''

Preston got down on one knee when the pair were holidaying in Isla Grande, Colombia.

Speaking about the trip, Julia said at the time: ''That's where we got engaged. All around, it was a really wonderful trip.

''We stayed on an island that was really beautiful and there was a lot of great snorkeling. The city was really nice, too, but because I live in the city the natural scenery was really great.''