Dennis Quaid has certainly had his ups and downs since making his film debut in the mid-seventies. He seemed destined for the stars in The Right Stuff, but plumbed the depths in Jaws 3-D. It took the sexy New Orleans thriller The Big Easy to fully exploit his roguish charm in 1987.

It turned him into a leading man with more than a little edge and subsequent roles included Jerry Lee Lewis in the biopic Great Balls of Fire and Doc Holliday in Wyatt Earp. He got good reviews, but too often his films missed the mark at the box office and directors steered clear of him. Drink and cocaine did not help, and he never quite fulfilled his A-List potential.

He gets the chance to change the past in the surprise hit Frequency, but, perhaps surprisingly, there is nothing Quaid would alter in his own life except "a few wardrobe changes back in the seventies". "Other than that, I don't know," he says with just a hint of Texan drawl. "My life is really too good to screw around with."

Quaid long ago sorted out his personal problems and he has been happily married for nine years to actress Meg Ryan, whom he met while making the sci-fi comedy Innerspace. Her career has overshadowed his, but the one-time heartthrob has returned to the upper reaches of the US charts in Frequency, a cerebral thriller with a novel twist on time travel.

Quaid's character dies in a fire in 1969, leaving a wife and young son. Thirty years later, John (Jim Caviezel from The Thin Red Line) is mucking about with his father's old radio set, makes contact with another broadcaster, and realises it is Dad, sitting at the same desk three decades earlier.

This is science fiction with an emphasis on ideas rather than special effects. "In the end it's more of a character-driven film, the idea of communicating with a dead loved one over time," says Quaid, looking relaxed on the satellite video link between England and Beverly Hills.

John warns his father about the fateful fire and saves his life. However, dad has still not made it to the present day. And, even more distressingly, John's mother is now no longer around either, the victim of a serial killer, whose life has also been saved by John's intervention in history.

Quaid got the role of heroic New York fireman Frank Sullivan only after the film-makers tried for various younger, hotter actors. The radio conversations between the instinctive, baseball-loving father and his more introspective son are the emotional heart of the film, and originally the father was meant to be younger in 1969 than his son is in 1999.

Ed Burns and Fifer Dougray Scott were lined up for the role, but first Burns dropped out and then Scott's involvement fell victim to the scheduling nightmare of Mission: Impossible 2.

The film-makers decided they would, after all, prefer an older, more mature man in the role of the all-American father, none of which qualities one would have associated with Quaid in the past, whose image has always been that of a laid-back hellraiser, if there is such a thing.

But, at 46, this is a new Dennis Quaid, still relaxed, still handsome, but seemingly more stable in real life, a husband and father of an eight-year-old boy. He and Ryan take it in turns to make movies, while the other stays with Jack in LA or on the ranch in Montana. Quaid stayed home while mom has been off in filming in South America with Russell Crowe.

Quaid likes to look for something different in his scripts. In recent years, he has proved a dependable lead in solid, if unspectacular, films, playing knight to Sean Connery's dragon in Dragonheart and Dad to twin daughters in the remake of Disney's The Parent Trap. Frequency was both different and attractively familiar.

Quaid is old enough to remember The Twilight Zone, the sixties TV series that regularly dealt with time warps. Mention of it prompts a voyage down memory lane, with Quaid listing favourite episodes.

He also felt he could relate to Frequncy as a father and it made him think about his relationship with son Jack. "My son was six years old while we were filming the story, so he was the same age as the 'little chief' in the film," he says.

"I'm also a son as well," he adds. Quaid was very close to his father, an electrical contractor, who was a drinking buddy and enjoyed the fast life, refusing to moderate his lifestyle even after several heart attacks.

"He died about 12 years ago. And there are certainly conversations that I would love to have with him, especially now that I'm older. He was 63 when he went, which isn't really very old these days and I'm sort of mad at him that he didn't get to have a relationship with his own grandson."

He is not surprised Frequency became a hit, largely on the strength of positive word-of-mouth. "I think people relate to the story of it." He believes unresolved father issues are common among "us guys", while the notion of time travel appeals to everyone.

"It's a fantasy we all have, because it seems like we, as human beings are never really satisified with the here and now." He seems not to notice that this flies in the face of his earlier comment about wanting to change nothing in his life.

Even as a child, Quaid loved movies and The Last Picture Show launched the film career of his bigger, gawkier brother Randy, while Dennis was still at school. A decade later, they would appear together in The Long Riders, a retelling of the Jesse James story, with four sets of actor brothers, co-written by Scot Bill Bryden.

But acting was not Quaid's first career choice and Frequency allowed him to fulfifl more than one fantasy. "I wanted to be a fireman, I think, when I was about five years old," he says. One of the attractions of acting for Quaid is the opportunity to dip into other people's lives.

"I went around with the firemen of New York City for about a month before we started shooting and they're a great bunch of fellahs. They're a very optimistic group of guys who sit around and rib each other and kid each other and then they go out and they give their lives for people they don't even know."

Quaid survived the shoot, but not unscathed. Acting on his son's advice, Frank finds a way out of the burning building that would otherwise claim his life, sliding down a chute, except the escape did not go quite as smoothly as planned.

"I took 20 stitches in the side of my head going down the slide with the stunt girl," says Quaid. "They had a pole that was a little too close. So we had to shut down for a half-day." If only someone could have radioed him from the future to watch out for that pole, he could have avoided all that pain and hassle.

But is there no advice the laid-back Big Easy star would give his younger self? He ponders the question for a moment. "I think I would just have told myself to take it easy," he says. It is a typical Dennis Quaid moment.