Keep an eye on Mila Kunis' burgeoning baby bump, because according to one report, she may be expecting more than one child with her fiance, Ashton Kutcher.

According to the latest issue of OK! Magazine, Kunis, 30, is four months pregnant with twins by Kutcher, her 36-year-old fiance and former "That '70s Show" co-star. "Ashton and Mila feel like they won the baby lottery," an unidentified friend told the magazine, adding that despite pregnancy being a shock, the acting twosome couldn't be more excited. "They're over the moon," said the insider.

According to the tabloid, the couple, who have yet to confirm the news of the pregnancy, were photographed discovering the baby news on March 10. In photos from the report, the actress can be seen sporting baggy clothing and high-fiving Kutcher while dining at an outdoor cafe in Los Angeles earlier this month.

Ashton Kutcher Cast member Ashton Kutcher poses at the premiere of "Jobs" in Los Angeles, California August 13, 2013. Photo: Reuters

Despite their engagement occurring just one month before the pregnancy claims (and just four months after Kutcher's divorce from actress Demi Moore was finalized) the reports states that the duo are ready for their rumored twins to arrive. "It was a total shock for both of them but they feel up for the challenge," said an insider, adding, "It didn't seem like it was possible for them to fall any deeper in love, but the prospect of raising an insta-family together has solidified their commitment to each other."

While the couple isn't speaking out about their rumored pregnancy just yet, OK! claims that the A-listers have already started working on their nursery. "[Ashton] commissioned custom-designed cribs and he's choosing colors and bed linens for the nursery," a source revealed. While Kutcher, a twin himself, is involved in the decorations, Kunis is also reportedly hands on in creating a "simple" environment for her children. "Mila has a number of friends with kids, so they've been giving her advice," said the source.

Us Weekly was the first to confirm the pregnancy Sunday night. According to the report, multiple sources have confirmed that the duo is expecting their first child together, a source stating, "This is something they both wanted. They are both so happy."

Kunis and Kutcher's engagement was first announced in late February following weeks of rumors. The couple first met on the set of the now defunct sitcom "That '70s Show" in 1998 while Kunis was 15 and Kutcher was 20. The actors played on-again, off-again flames in the series before its finale in 2006.