The musician, who was one of only two people ever awarded an Emmy, a Grammy, an Oscar, a Tony and a Pulitzer Prize, passed away at the age of 68 following a brief illness.
Friends, colleagues and fans have flooded Twitter with condolence messages, and deaf actress Matlin took to her page on Tuesday (07Aug12) to mourn the loss.
She writes, "Sad to read of the passing of composer Marvin Hamlisch. We worked together last Christmas at Kennedy Center; truly a gentleman. RIP."
Hairspray star Ricki Lake adds, "So shocked & sad to hear about Marvin Hamlisch. They're Playing our Song was one of my very favorites. What a loss!" and Seinfeld comedian Jason Alexander tweets: "So saddened by the passing of my friend, Marvin Hamlisch. So often, he was truly 'the one'. The music of Heaven got sweeter today. RIP."
Veteran actress Patty Duke has also added her tribute to Hamlisch, posting: "RIP Marvin Hamlish (sic). I have such fond memories of 'our' piano player on Valley of the Dolls. What a terrific man!"