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."