Jennifer Lawrence "cried" before singing Mockingjay's 'Hanging Tree'

Jennifer Lawrence was reduced to tears at the prospect of singing in The Hunger Games: Mockingjay - Part 1.

Director Francis Lawrence said that the actress was "horrified" about having to perform, but added that her vocals were "great", Radio Times reports.

In Mockingjay, Katniss Everdeen sings 'The Hanging Tree', a song she learned from her father when he was alive. 

The director explained: "She'd probably tell you it was her least favorite day. 

"She was horrified to sing, she cried a little bit in the morning before she had to sing. But she did it and she did it all day - and she hated me for making her do it all day - but she did and it's great. 

"She'll probably never really understand it because she's so sensitive about the singing."

He continued: "The Lumineers sent the melody over and then we had a vocal coach, who sort of shifted the key for Jen's voice.

"Then she started working with Jen once or twice - Jen didn't really want to do too much of the training [he laughs] - but she recorded it for me as a test so I could hear it. 

"I was worried, I really thought we were going to have to do a bunch of pitch shifting, but she sounded great. What you hear in the movie is what she did on the day in the quarry."

Mockingjay - Part 1 will open on November 20 this year and Part 2 is scheduled for release on November 20, 2015. 

Once the Lionsgate film franchise has wrapped up, The Hunger Games will move to London for a stage production in summer 2016.