But it turns out R-Pattz, 25, isn't afraid of belting out a tune either. The actors had a lot of fun filming the vampire movies together.
'Every Wednesday the entire cast would go for a karaoke night,' reveals Rob's Twilight co-star Judi Shekoni, 33, who plays Zafrina.
And the stars of the saga didn't limit their partying to a weekly sing-song.
Rob and the other cast members - including Kristen Stewart, 21, and Taylor Lautner, 20 - always celebrated each other's birthdays by hiring private rooms in sushi bars and dressing it with balloons.
'We had one amazing night out at a club where everyone was dancing and we were out until the early hours,' says Judi.
'The hotel bar was also a great place to hang out - you'd always find a few vampires or Volturi sitting around drinking!'