The 'Twilight Saga' actor - who recently reunited with girlfriend Kristen Stewart after she cheated on him with director Rupert Sanders - has been known by the nickname for several years, but he has never liked it and would like to injure the person who came up with the name.
He said: "I would like to break the hands and mouth of the person who came up with it."
Despite reconciling with Kristen and enjoying a night out at the Chateau Marmont in Los Angeles together, the pair have so far been promoting the final part of the 'Twilight' series - 'The Twilight Saga: Breaking Dawn - Part 2' - separately.
British heartthrob Robert is struggling to trust Kristen again after she was pictured kissing 'Snow White and the Huntsman' filmmaker Rupert.
A source said: "Kristen is working hard to try and force the relationship into what it was before.
"But the truth is, she's going to have to take it slowly with Robert because he's still having trouble trusting her again.
"For him to carry on like nothing happened is very hard. Kristen is eternally sorry for cheating on him and he has forgiven her - kind of."