TORONTO -- Pass the lab coat, wacky printed shirts and hair teaser.

"Back to the Future" star Christopher Lloyd is eager to play Doc Brown again.

"If they want to do some more, have Doc appear in a film, film a cameo, I'm happy to do it," the 76-year-old actor, who played the passionate, frizzy-haired scientist in the "Back to the Future" films, said in a telephone interview.

"I love the character and I love doing it."

Lea Thompson, who played Lorraine Baines-McFly, would also consider reprising her character, should a fourth film be contemplated.

"I would never say 'no' to a big feature film," she said. "No one's offering them to me, so if they said 'ya,' I would do it.

"But I don't think it's gonna happen."

The beloved franchise celebrates a milestone on Wednesday: Oct. 21, 2015 was the exact day and year that Marty McFly, played by Canadian Michael J. Fox, travels into the future in the second part of the series.

To mark the event, Cineplex Entertainment will screen "Back to the Future" parts one and two in theatres across the country on Wednesday, followed by the full trilogy on Sunday. A portion of ticket sales will be donated to Team Fox, benefiting the Michael J. Fox Foundation.

Lloyd said the first film, which hit its 30th anniversary in July, lit a flame under his career as hot as the one that burns behind Doc's DeLorean car when it blasts through time.

"The film 'Back to the future' certainly did a lot to put me where I am today and I did not foresee that," he said. "I just was hoping the film would open successfully, the first one, but it's gone way beyond what I think most of us have imagined.

"It doesn't quit."

The franchise even led to a personal milestone: His first onscreen kiss.

It was with Mary Steenburgen, in "Back to the Future Part III."

"Not only was it my first, it was my only," said Lloyd. "I can't think of a film where there's been a romantic kiss of any sort, so I treasure that."

For Thompson, playing Marty's mom in two different time periods and with different mindsets established her "as somebody who can act," she said.

"Not every part is a real acting kind of tour de force like that was, for me, and Tom Wilson and Chris Lloyd and Crispin Glover."

Robert Zemeckis directed the three "Back to the Future" films and also co-wrote them with Bob Gale.

Lloyd said an early draft for the first film had Doc Brown going to an atomic test site in New Mexico with Marty in the DeLorean, to get energy to travel into the future.

But they changed it.

"I'm glad they did," said Lloyd. "I think it would've put a kind of darkness to the film I don't think they wanted."

Lloyd said he still has one of the shirts Doc wore in "Back to the Future Part II."

"It's more or less yellow with little steam engines going around on it. I haven't been wearing it. It's just hanging in the closet all these years."

And he still keeps in touch with Fox.

"We've had a chemistry that just is innate," said Lloyd. "We didn't have to figure out how to bring our chemistry up to the level that was necessary for the film. It's just present automatically and so it's been great.

"We've had quite a ride."

Thompson also has some memorabilia from the set.

"All I have is the pink prom dress and the shoes," she said, adding with a laugh. "I used to have those fake boobs from 'Back to the Future II' but they got too smelly. They were latex."