London, Oct 13 (TIWN) Actress Kristen Stewart, who portrays Princess Diana in the new biographical drama film 'Spencer', says it was a nerve-wracking experience, and the anxiousness led her to develop a pain in her jaw.

The 31-year-old actress portrays Princess Diana in the new biographical drama film, but she admits it was a nerve-wracking experience, and the anxiousness actually led Kristen to develop a pain in her jaw.  Kristen - who plays the late Princess as she spends three days with the Royal Family over Christmas in 1991 - told told BBC News: "I had TMJ [her jaw stayed shut] to the point where I was like, completely locked up. 

"I was like, 'Huh, I guess I'm really nervous - I was really tripping out until we started."  The Hollywood star revealed she didn't actually know a huge amount about the Royal Family before she accepted the role.