The One in the Same Theory

I had a theory going for about 30 minutes that Vince Vaughn and Vincent D'Onofrio were in fact the same person. Just taking a unique approach to proving himself a veritable comedic and dramatic actor, perhaps an alter ego (Vaughn) that was never supposed to become such a popular actor and now he's stuck in a dual life. I was quite committed to this theory and I was going to propose you all out there to provide me with evidence that I am wrong.... But I found it myself. They appeared in the same movie, in the same scene in The Break Up.