In a career milestone, Steve Martin was honored Sunday with one of the nation's top comedy awards – the Mark Twain Prize for American Humor.
But ask his friends and colleagues what makes him so funny and they'll tell you it's his smarts, not his silliness.
"He's eerily smart, it's unnerving," Claire Danes, who stars opposite Martin in Shopgirl, the newly-released film adaptation of his novel of the same name, tells PEOPLE. "He has one of the most sophisticated minds I've ever seen."
"He's a genius," agreed longtime pal and fellow comedian Martin Short on at the Kennedy Center in Washington D.C., where Short along with Tom Hanks, Queen Latifah, Paul Simon, Diane Keaton, Larry David and Lily Tomlin gathered to honor Martin.
Diane Keaton, who starred with Martin in Father of the Bride, stole the show Sunday when she serenaded him with "The Way You Look Tonight."
And though his colleagues emphasized Martin's intelligence, Tomlin praised Martin's "divine absurdity," not to mention his body that's seemingly "made out of rubber." Added Tom Hanks: "Laurel and Hardy defined an era. Steve defined ours."
The ceremony included clips from Martin's decades-long career – including his famous King Tut song from Saturday Night Live and his role as one of the "two wild and crazy guys" – plus old appearances doing standup on The Tonight Show.
In accepting the prize, Martin, 60, mentioned some other awards he had won, including a 1969 writing Emmy for The Smothers Brothers Comedy Hour. "But of course the Mark Twain Prize is more special to me," he said, "because it's more recent."
Asked if he thought his comedy was similar to Twain, Martin told PEOPLE modestly: "He's a giant among us. I'm lucky to get an award with his name on it."