He 说 as much in an interview he did in 伦敦 while promoting My World 2.0. Basically he 说 that it depends on the situation, but that he would do it. Justin isn't only up for dating other stars, he would 日期 anyone if she was the right sort of girl.
And another detail: Justin likes girls with nice smiles, pretty eyes and who can make him laugh. This is his 描述 of his dream girl. Do 你 fit the mold? The 你 may be just right for Justin!