If you impersonate another actor for profit claiming to be him/her you may be facing legal action. There is a difference in selling yourself as "Scarlett Johansson" vs. "A Scarlett Johansson impersonator" vs. your own name/stage name. If it's covert and deceiving, you are in trouble, if it is overt, you are fine and that's why they world has so many Elvis impersonators. Although I see a new market opening for Kate Moss impersonators https://news.ycombinator.com/item?id=40498668
When it comes to works of art, if you tell the buyers/viewers it's yours you are fine, but if you paint a copy of a famous painting and claim it to be the original one, you are a criminal.