Gwyneth Paltrow and Charlize Theron are the latest stars to attend the Toronto Film Festival, bringing films already touted as potential Oscar contenders.
Paltrow was unable to attend the Venice Film Festival last week
Paltrow was promoting Proof, premiered last week at the Venice Film Festival in her absence after transport problems stranded her in the US.
North Country, Theron's latest movie, was inspired by America's first major sexual harassment case.
The festival, which is celebrating its 30th birthday, runs until Saturday.
Both North Country and Proof see their stars tackle non-glamorous roles in the kind of issue-based dramas that often find favour with Oscar voters.
Theron, who won an Academy Award for playing a serial killer in Monster, told reporters that Hollywood places too much emphasis on physical beauty.
In North Country, directed by New Zealander Niki Caro, who was also behind the film Whale Rider, she plays a single mother who rallies women workers to rise above the abuse they face at a local mining company.
"When I started telling people about this story, some people looked at me and said, 'You're doing another ugly movie.'
"All we discussed was the truth of this woman and the life she's led.
"When you get the answer to the emotional side, the physical elements just come quite organically."
Proof sees Paltrow play a woman mourning the death of her mathematical genius father - a role she first played on the West End stage.
Between the stage and film version Paltrow's own father died, though she said she was not sure if it had influenced her performance.
"I think it probably did in a way," she told reporters.
"I don't transplant my emotions from real life and put them in what I'm doing, but I was on a very parallel path."
In North Country Theron plays a miner who suffers sexual harassment
Proof was directed on both stage and film by Britain's John Madden, who steered Paltrow to an Oscar in 1998's Shakespeare in Love.
"The performance evolved as you would expect," he said.
"I think that couldn't help but to make it a little more poignant when she came to do the movie because her father had died by that point."
Paltrow was joined on the red carpet by co-stars Jake Gyllenhaal, Hope Davis and Sir Anthony Hopkins.
Monday's premiere was also attended by Scottish actor Alan Cumming and Red Eye actress Rachel McAdams.
Theron, meanwhile, faced the cameras alongside her fellow North Country actors Sean Bean, Sissy Spacek and Woody Harrelson.