Tilda Swinton got a surprise elbow to the face from Dev Patel on the set of their new film The Personal History of David Copperfield

Tilda Swinton got more than she asked for on her first day making her new film The Personal History of David Copperfield.

The Oscar winner, 58, has a supporting role in the latest film from Veep creator Armando Iannucci, based one of Charles Dickens’ most beloved novels, which takes place in 19th-century England as it follows its hero’s wildly unpredictable journey (Slumdog Millionaire‘s Dev Patel plays the titular role.)

As Patel, 29, recalled to PEOPLE and Entertainment Weekly at the Toronto International Film Festival, where the film had its world premiere on Thursday, he came extremely close to injuring his costar when filming their first scene together.

“I accidentally elbowed Tilda in the mouth,” he said, while seated next to his other costar Hugh Laurie and Iannucci. “I was so nervous. It was my first scene with her. There’s a whole thing where he’s almost about to pass out and he’s trying to find a couch to land on and I was spinning around and flailing and I kind of did like a UFC elbow. And Tilda just stopped and I thought, ‘I just broke Tilda’s teeth in the first scene.’ And she was very gracious about it. All of her teeth are intact.”

Hugh Laurie, Dev Patel, and Armando Iannucci
The Personal History of David Copperfield‘s Hugh Laurie, Dev Patel and Armando Iannucci
| Credit: Celeste Sloman

Actors who have previously played Copperfield onscreen have generally been white, including Daniel Radcliffe, who starred in the 1999 BBC adaptation. For his own take on the material, Iannucci chose to go the colorblind route, casting Patel, who was born and raised in London to Gujarati Indian Hindu parents, and filling out his ensemble with a diverse group of actors.

Patel told PEOPLE he was grateful to have “a chance to play in that world of costume and horses and carriages. “What would 6-year-old Dev think of me doing this now?” he marveled.

The Toronto International Film Festival runs through to Sept. 15.