Earlier this month, the pair was spotted lunching at LA's Soho House, with sources claiming they looked more than just friends.
"They were seated on a couch on the same side of the table and Mila was running her hands through Ashton's hair," a source told Us Weekly about their cosy outing.
"She had her elbow resting on his back and couldn't stop playing with his hair and rubbing his shoulders. He leaned in and whispered to her and kissed her cheek."
But since the pair was first spotted together back in April, they've gone out of their way to deny suggestions they've taken their friendship to the next level.
"It's absurd!" Black Swan star Kunis told Extra at CinemaCon 2012 in Las Vegas. "A friend is a friend."
A rep for Kunis also piped up to dismiss the rumours.
"They have been friends for years and had dinner with a bunch of people that night," the rep told the New York Daily News.
"No! They're so not dating," the rep echoed to Us Weekly. "They've been friends for years. But she would never ever. Definitely nothing going on there."
And if that lot didn't put you off the scent, Kunis, who split from long-term boyfriend Macaulay Culkin in 2010, again brushed off the romance rumours during a recent interview with Elle magazine.
"I am totally single ... Listen, we hang out," she told the mag.
"We've known each other for 15 years. We have mutual friends. We're comfortable with one another. That's it! There's no crazy love story, nothing more."
She added: "I am very private and I've never commented on my personal life. Realistically, if I was seeing somebody, do you think I would tell you?
"I would still give you the bulls**t answer of, 'I don't comment!' But the truth is, I am really single."
Single, or doth the lady protest too much?
And while snaps of Kunis and Kutcher help fuel a thousand rumours, the actor's estranged wife Demi Moore is said to be "beyond heartbroken" over his new romance.
A source told webloid RadarOnline: "Demi is devastated that Ashton has moved on so quickly and is dating Mila. She is beyond heartbroken.
"Even though Ashton cheated on her all the time, it was with random girls, it wasn't a relationship like it is with Mila and that is what is killing Demi now.
"Seeing photos of him kissing another woman is too much for her to handle, it's like having her nose rubbed in it time and time again. She kind of knew it was definitely over between them but I think she was still holding out a little hope for a reconciliation - now he's actually dating someone else she knows that's not going to happen."
Added the insider: "Each time Demi hears about Ashton and Mila it breaks her heart. She really loved him despite the flaws in their marriage and to see him dating someone new, who is so much younger than she is, is like a knife in her heart."
Meanwhile, Kutcher took to Twitter today to have a pop at the prying paparazzi.
"Apparently the privacy of your own home is no longer the privacy of your own home #societyfail," he wrote.
I'd definitely go for more shrubbery.
The briefs
And finally...
* "My heart aches and breaks"- Anne Hathaway responds to Colorado shooting.
* No Doubt rock the Teen Choice Awards with new single, Settle Down.
* Hoff heist: Thieves make off with hundreds of David Hasselhoff cardboard cutouts.
* Mariah Carey announces new single, edges closer to deal on American Idol.
* Going strong: Kim Kardashian and Kanye West's date night in Miami.
* Spice Girls to perform at Olympics closing ceremony, spouts the Daily Mail. Rumours of a rift between Ginger and Posh resurface. Oh, happy days!
* Superman takes flight in two new Man of Steel trailers. Nice laundry, Supes.
* High hopes: Lindsay Lohan wants to remake Thelma and Louise with Jennifer Lawrence.
* Missing Terminator 3 star Nick Stahl back home with estranged wife.
* Katherine Jackson says she's "fine" after being reported missing.
- Blogger Bites Back
