Zac Efron 'almost had a mental breakdown' while playing Ted Bundy

Actor Zac Efron has revealed that he "almost had a mental breakdown" during the filming of "Extremely Wicked, Shockingly Evil and Vile", in which he plays the role of real-life serial killer Ted Bundy.

In an interview with Entertainment Tonight, Efron said that his co-star Lily Collins raised the performance bar so high during production that he started to doubt his calibre.

"The first day of filming, I'll never forget. It's freezing cold in Kentucky, I smell like a thrift shop because my clothes were all from the '60s and I was just getting used to walking in this style. I walk in and I know my lines, I'm ready for the day and it was the first warm-up scene, and Lily was ready to go right then at rehearsal, perfect. Gave a perfect performance on the rehearsal, and I literally walked outside and I almost had a mental breakdown," Efron, 31, said.

I was like, 'We didn't even get to rehearse and Lily is going for awards already?' (She's) so good. And I just sat at home and said, 'Zac, you got to be better, you gotta be better, how can you do it?' And I figured out how," he added.

The biographical crime thriller, directed by Joe Berlinger, focuses on Bundy, who confessed to killing at least 30 women during 1970s.

The story is told from the perspective of Bundy's ex-girlfriend Elizabeth "Liz" Kloepfer, portrayed by Collins.