If names like Olivia Wilde and Vin Diesel sound too good to be real, it's because they are. While seeking fame and fortune, a number of well-known celebrities have ditched their given names, which makes sense when you find out what their birth names were. Tom Cruise's original moniker, for example, would've hardly fit nicely on a movie poster. Test your knowledge of these 19 celebrities' pre-fame life and see if you can correctly choose their birth names. 

Sources: POPSUGAR | Bustle