Ashton Kutcher Cheating on Mila Kunis, Couple 'Not Exclusive?' 'That 70s Show' Lovers Defy Rumors with Sexy PDA at 'Oz' Premiere Party

So how's the best way to stir some shady gossip surrounding the adorable relationship between former "That 70s Show" co-stars Ashton Kutcher and Mila Kunis - by talking to one of Kutcher's bitter ex-lovers, of course! Sarah Leal (the woman Kutcher allegedly hooked up with while still together with Demi Moore) recently told Star magazine that she spotted a pic of the 35-year-old actor "chilling in PJs" with a secret woman he's allegedly dating on the side. Leal admits that the photo could be "totally innocent," but also claims that Kutcher and Kunis are definitely not an exclusive couple. Right... which is why the duo was spotted cozying up and packing on some heavy PDA at a recent "Oz" movie premiere party. Looks like they're pretty exclusive to us!

According to Star magazine, Kutcher and Kunis' budding relationship "isn't all it's cracked up to be." The gossip tabloid recently caught up with Leal, and although she hasn't seen the "Two and a Half Men" star since October 2011, she does reveal that "in December, a coworker approached her with a mysterious picture of the actor in his pajamas, text-messaged by an anonymous friend who claimed to be dating him behind Mila's back."

Well, that's totally normal...

Leal goes on to explain, "Apparently the girl was at Ashton's house in L.A., and obviously someone was with him, but he didn't know he was in the picture. It was creepy."

So who exactly is this mystery women allegedly photographing Kutcher posing in his PJs, fans may ask? "I didn't get the girl's name; I didn't really care," Leal stated. "It could be just an innocent picture, but I think it's also possible he's not dating Mila exclusively."

Hmm, if anything it sounds like Leal might be just a tad-bit jealous...

Gossip Cop reached out to one of Kutcher's reps, who insists that Leal's claims are "completely insane."

Instead, it looks like Kutcher and his "Sexiest Woman Alive" are doing quite well. The 29-year-old starlet showed up to the L.A. premiere of her upcoming film "Oz the Great and Powerful" solo, but insiders report that the couple arrived to an official after-party holding hands around 10:30 p.m. One fellow partygoer tells Us Weekly that the duo enjoyed a nice dinner before heading to a reserved section at the Lure nightclub. They spent the rest of the evening cozying up side-by-side - Mila even ended up sitting on Ashton's lap the insider reveals. Then a little after midnight they were spotted kissing as Kutcher "wrapped her in his arms" and Kunis leaned her head on his shoulder. How cute!

Kutcher and Kunis have kept their budding relationship on the down-low, although they've been spotted together on numerous occasions since the summer.