Diane Portwood gives two thumbs up to her son Ashton Kutcher's new comedy, Just Married. But Kutcher and costar Brittany Murphy's performances as lovey-dovey honey-mooners? Nothing to write Oscar about. "It's like, 'Are those two even acting?'" says Portwood, 50. "They act the same way here at home." On visits to her house in Homestead, Iowa, "they're always holding hands, goofing around, wrestling around on the floor the way people in love do," Portwood says. "It makes a mother happy to see someone actually care for your child as much as you do."

Offscreen, Kutcher, 24, and Murphy, 25, are closer to Just Started Dating than to saying "I do." But the strapping 6'3" star of TV's That '70s Show and the 5'1" movie spitfire (Clueless, Don't Say a Word, 8 Mile) have quickly secured a lip-lock on the title of young Hollywood's hottest new couple. They hosted MTV's New Year's Eve broadcast and regularly smooch up a storm from Manhattan nightclubs to L.A. red carpets. The romance began to blossom around October. "When we were doing the movie, we were just friends," says Kutcher. "We just kind of started hanging out more. And now we've been hanging out a lot more."

Just Married director Shawn Levy recalls that "from the minute they met they were bouncing off each other, riffing, kidding around and laughing." During breaks shooting the movie in Venice last winter, Kutcher and Murphy took in the sights while chattering in invented Italian. "We would walk around speaking this fake language and making the other tourists feel stupid," says Kutcher. He also came to Murphy's rescue in the Alps. "They went jogging, and we were at a pretty high altitude," says Levy. "Brittany got lightheaded, and Ashton gave her a piggyback ride all the way home. He has this goofy persona, but he's a romantic at heart."

Family ties figure strongly for both actors. Raised in Edison, N.J., by solo mom Sharon, 50 (who split with Brittany's father when she was a baby), Murphy began acting in sitcoms as a teen. She still lives with Mom in L.A. "She's my angel," Murphy has said of Sharon.

Kutcher, the son of factory workers (his mother was divorced from Larry Kutcher, 53, in 1991, and wed construction worker Mark Portwood, 40, in 1996), was a freshman biochemical engineering major at the University of Iowa when he won a statewide modeling contest in 1997. Soon he was appearing in Calvin Klein jeans ads and within months was cast as lovable lunkhead Michael Kelso in That '70s Show, now in its fifth season.

When Just Married began shooting, Murphy was fresh from a reported romance with her 8 Mile costar Eminem. Kutcher was seeing Birds of Prey star Ashley Scott, 25. However, the costars "are absolutely truthful when they say they didn't hook up until well after we shot the movie," says director Levy. "No one believes them." Maybe because they have been sporting matching rings (simply a tribute to the movie, says Levy). They're not engaged, says Kutcher's mother: "They're just taking it slow, seeing where it goes." She, however, is already rooting for a real-life Just Married remake: "I'd like to see it," she says. But "they need time."

Samantha Miller
Sona Charaipotra and Sharon Cotliar in New York City, Lauren Comander in Chicago and Rachel Biermann and Ulrica Wihlborg in Los Angeles

  • Contributors:
  • Sona Charaipotra,
  • Sharon Cotliar,
  • Lauren Comander,
  • Rachel Biermann,
  • Ulrica Wihlborg.