A celebrity or his/her estate may sue you and you may be found liable if you do not ask permission. By using their image (even if they are artist renditions) you are denying them control of their right of publicity. Basically a celebrity has a right to control the use of their name, likeness, and identity. You are exploiting their name and likeness for commercial profit. The more prominent the picture of the celebrity is in the restaurant the more likely the celebrity would want to sue.

Additionally, I do not believe you would have a claim of copyright preemption here. Copyright law may preempt a right of publicity claim if the value that is derived is mainly from the piece of art and not from the celebrity.

As for the Andy Warhol rendition of Marilyn Monroe, a recent court decision ruled that MM does not have a right of publicity. This is because she died in New York and NY does not recognize a right of publicity post-mortem.

If you really want to do this, then you should either ask permission or consult a lawyer. Sometimes the celebrity may grant you permission. Sometimes the celebrity lost his or her right of publicity upon death and sometimes this right has expired.

http://jlaufirm.com

http://jasonlauip.blogspot.com

Permission would be needed from the artist (or his manager, estate, etc., whomever owns the rights currently) for use of the material, under copyright law. In some cases, it might also be necessary to obtain permission from the person portrayed, but not always, and for a different reason (privacy, not copyright). However, invasion of privacy and related torts are hard to establish when the would-be plaintiff is both a publicity-seeker and consented to creation of the artwork (or is dead at the time an artist creates it).