The couple first met as teenagers on the set of That ‘70s Show and since the she has enjoyed a longterm romance with Macaulay Culkin, while he was married to Demi Moore.
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However the loved up pair have worked together once more on Ashton’s sitcom and fans can’t wait to find out if their chemistry is intense when the programme airs in America April 10. In new screen shots from the CBS network show, Mila – who plays Vivian – makes her debut as "a young, beautiful, free-spirited world traveller".
She gets romantic with Ashton's character, Walden, however he was planning to propose to someone else before she came along. Snaps show them enjoying a Chinese takeaway meal with beers at his kitchen table and what looks like Mila’s character camping in the back yard.
Multiple sources have confirmed that the actress is expecting her first child with her fiancé. "They are both very, very happy," a friend of the couple told People. "It's still early."
The exciting news comes one month after the couple's engagement was revealed. The long-time friends started dating in 2012. Mila, 30, and Ashton, 36, were spotted kissing at a basketball game in Los Angeles on Saturday, where the bride-to-be happily showed off her beautiful engagement ring.
The stars locked lips when they were spotted by the Kiss Cam, much to the delight of the crowd. It remains to be seen whether Mila's pregnancy means wedding plans are put on hold for the time being. According to reports, the couple were in no hurry to walk down the aisle, with friends reporting that they haven't started planning their big day yet.
Ashton and Mila haven't worked together for a long time