She's 41, he's 25. She has three kids, he has a lot of trucker caps. Sounds like the perfect recipe for wedded bliss, right?

Well, don't check your mailbox for an invitation just yet. Ashton Kutcher's publicist is blasting the latest round of tabloid reports saying the "That '70s Show" actor is engaged to Demi Moore.

"It's bulls--t," Kutcher's publicist, Matt Le Bov, tells PEOPLE.com. "(A tabloid) called us about it. We told them it's not true. They went with it anyway. I wish I had my own magazine so I could just make up s--t."

The two have been in the news of late not just for their romance -- which has been making headlines since last summer -- but also because Kutcher has been making the media rounds for his new sci-fi thriller, "The Butterfly Effect," which opens Friday.

Not helping the rumor mill, of course, is Kutcher's penchant for pulling practical jokes (usually via his MTV hit "Punk'd"). The kidding continued Wednesday on NBC's "Today" show, when Katie Couric asked the actor about his relationship with Moore.

Kutcher became enraged. "See, this is exactly why I wanted to do the interview with Matt," he exclaimed. "You said you weren't going to ask about this!" He then got up as if to remove his microphone and storm out.

Turns out, however, it was just a prank, and Couric was in on the whole thing. "See, that's uncomfortable, being punk'd," Kutcher said, sitting back down.

Where the marriage rumors are concerned, it's a little less clear who's getting punk'd. Since last summer Kutcher has accompanied Demi and brood (Rumer, 15, Scout, 12, and Tallulah, 9, her kids with ex-husband Bruce Willis) to awards shows and premieres, and the couple showed up this past week at the Sundance Film Festival together.

As PEOPLE reports in its latest issue (on newsstands Friday), Kutcher and Moore hit a party after the premiere of "The Butterfly Effect," where Moore asked for a Levi's skirt to be embroidered "Dashmi" -- their names combined.