TORONTO -- Many actors coolly shrug off Academy Awards buzz when asked about it on the film festival circuit.

But as newcomer Lupita Nyong'o reflected on the Oscar talk surrounding her heart-rending performance as real-life plantation worker Patsey in "12 Years a Slave," her emotions got the best of her.

"It's so exciting," the affable Kenyan actress said before getting choked up in an interview at the Toronto International Film Festival.

"But it's also such a relief that I seem to have done her justice," she continued, tears streaming down her face after taking a moment to collect herself on a hotel room sofa.

"And at the end of the day, Patsey was my reward and everything else is welcome and overwhelming and beautiful."

Audience members at the festival have also been shedding tears over Nyong'o's role of Patsey in director Steve McQueen's powerful, based-on-fact story of Solomon Northup, played by Chiwetel Ejiofor. The 19th-century black free man was an acclaimed musician with a family in upstate New York before being kidnapped and sold into slavery in the Deep South.

Nyong'o's Patsey was a hard-working slave who suffered horrific abuse at the hands of the reprehensible Edwin Epps (Michael Fassbender) and his wife (Sarah Paulson) on their Louisiana plantation where Solomon wound up.

Co-stars include Benedict Cumberbatch as William Ford, Solomon's first master, and Paul Giamatti as a slave trader. Alfre Woodard plays a white plantation owner's wife, Paul Dano is a vile carpenter on Ford's property, and Brad Pitt (who also produces) is in the role of a Canadian abolitionist.

John Ridley wrote the screenplay that's based on Northup's autobiography.

McQueen, whose previous efforts include the acclaimed films "Hunger" and "Shame," doesn't pull any punches, delivering an unvarnished look at the brutality the slaves suffered -- particularly when it comes to Patsey.

Nyong'o said it was a "cathartic" experience seeing the film for the first time.

"I wept from the moment Solomon Northup is in shackles right until the very end, but it was like a relieving kind of experience as well, because Steve and everybody assembled put together such a beautiful piece of art and history, and I really felt that he did the autobiography justice and it was such a pleasure.

"I was happy to be such a wreck."

The Toronto International Film Festival runs through Sunday.