Simplify the following text for a Grade 4 native English-speaking person.
Original: With Jolson providing almost all the vocals , and veteran Columbia contractee Larry Parks playing Jolson , The Jolson Story ( 1946 ) became one of the biggest hits of the year .
Simplified: A movie about Jolson 's life , The Jolson Story , won Oscars in 1946 . Larry Parks played Jolson , but Jolson sang the songs himself .