Was Cleopatra pretty?

Cleopatra is depicted on the silver screen as a great beauty. We hear that Cleopatra seduced the great Roman leaders Julius Caesar and Mark Antony, and we assume that Cleopatra used her great beauty as a diplomatic aid in putting Egypt on a more favorable footing with Rome. However, we don't know whether Cleopatra was a beauty. Instead, what evidence we have seems to suggest she was not.