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Ashton Kutcher and Mila Kunis have been longtime friends since their days on "That '70s Show," but after several recent sightings together, including a weekend getaway, celebrity insiders are beginning to wonder if there is something more between them.

Kunis dashed any hopes of romance, telling "Extra," "It's absurd! A friend is a friend."

As friends, the pair went on a three-day getaway to the coastal town of Carpinteria, Calif., just south of Santa Barbara, where they dined on sushi and shopped for fruit and flowers at a roadside stand.

"Of course people are going to speculate," said Us Weekly's senior online editor Justin Ravitz. "If they were dating, it would be great story because they are great friends and former co-stars. And they look great together."

So far all industry watchers know is that they are spending time together.

Their weekend getaway comes not long after their April 15 dinner with a group of friends at L.A.'s Asanebo, when speculation of a romance first began.

Kunis' rep dismissed rumors then that the two were dating. "They have been friends for years and met up for dinner with a group of friends," her rep told People.

Neither her rep nor his responded immediately to ABCNews.com's request for comment.

"Mila is extremely private about her love life," Ravitz said, adding that it's possible the former co-stars' friendship has turned romantic, but they are keeping it under wraps. For now, though, it sounds like a "close friendship," he said.

Sources tell the magazine that Kunis, 28, is "too smart" and "too strong" to put up with the kind of behavior that reportedly ended Kutcher's marriage to Demi Moore.

Meanwhile, a source told People that Kutcher, 34, has long held a torch for Kunis. "He was so in love with her for a while when they worked together," the source was quoted as saying. "He thought she was a goddess, was always talking about how beautiful she is. But she was with Macaulay [Culkin] for a lot of that time and also just generally gave off a not interested vibe."

Though Kunis has been linked to a number of guys, including her "Friends With Benefits" co-star Justin Timberlake, her last serious relationship was with child star Macaulay Culkin. They called it quits in 2010 after more than eight years together.

Kunis' star has been on the rise following her role in 2010's "Black Swan."

"Her star is still ascending. We haven't seen her peak yet," Ravitz said. "Ashton is a guy along her trajectory. He's now the most highly paid man on television and a tech entrepreneur and he's still a Hollywood player."

While they both share a bawdy sense of  humor - Kunis appeared on Kutcher's show "Punk'd" - she  is less of a party girl than he is a party boy, Ravitz said. "I don't know if they have the right temperament for each other."