He 発言しました as much in an interview he did in ロンドン while promoting My World 2.0. Basically he 発言しました that it depends on the situation, but that he would do it. Justin isn't only up for dating other stars, he would 日付 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 説明 of his dream girl. Do あなた fit the mold? The あなた may be just right for Justin!