Bruce Willis on Demi and Younger Man

N E W   Y O R K, June 12 -- — Former "brat pack" member Demi Moore has been spotted frolicking around with current a teen idol, Ashton Kutcher, who is 15 years her junior — but her ex-husband isn't bothered by it.

Surprise sightings of Moore, 40, and Kutcher, 25, have fueled intense interest from the tabloids. But Moore's ex-husband, Bruce Willis, says he's not surprised at all by the romance.

"You, me, everybody we're all 25 in our heart," Willis said on ABCNEWS' Good Morning America.

"He [Kutcher] is … he's a young man. He's, he's a pretty cool guy," Willis said.

Camps for both actors haven't released any comments on the nature of the stars' relationship, despite photographic evidence in the new issue of People magazine.

The stars have been spotted together in Miami and L.A. since they met in late April while dining with a group at a swanky New York restaurant.

Kutcher, who plays a teenager in Fox's That '70s Show, has also starred in Dude, Where's My Car? In his new MTV hit show, Punk'd, Kutcher captures his peers on tape as they get sucked in by elaborate practical jokes. Justin Timberlake and Kelly Osbourne were victims of some of his most recent pranks.

After a five-year break from Hollywood, Moore has a bikini-sporting cameo in Charlie's Angels Full Throttle.Before she appeared in Ghost, a blockbuster hit that led to her status as one of the highest paid actresses in Hollywood, Moore was briefly a teen idol herself after securing a spot in the famous "brat pack" in 1984's St. Elmo's Fire.

Willis and Moore, who have three daughters together, were divorced in 2000, but they remain close and appear in public together regularly.

"I love Demi," Willis said. "We're still great friends. I wish her nothing but, you know, the best, and, and happiness, and whatever form that takes," he said.

Willis, who is the voice of the family dog, Spike, in the upcoming animated movie, Rugrats, admits that he dates younger women and says women should feel free to do the same.