NEW YORK — — "To the world he was a legend, an actor from the golden age of movies who lived well into his golden years, a humanitarian whose commitment to justice and the causes he believed in set a standard for all of us to aspire to," son Michael Douglas, in an Instagram post.

— "Kirk was one of those rarest creatures, a Movie Star as well as an incredible actor. A man who forged his own destiny & used his notoriety in an attempt to make some difference in the world. He was a gift, we were lucky to have him, and in some ways, we always will," Lee Grant, who co-starred with Douglas in the 1951 movie "Detective Story," on Facebook.

— "Kirk Douglas. The inspirational Scalawag. 103 years on this earth. That's got a nice ring to it! Great hanging with you man," Danny DeVito, on Twitter.

— "Kirk Douglas will always be an icon in the pantheon of Hollywood. He put himself on the line to break the blacklist. My love goes out to my friend Michael and the whole family," Rob Reiner, on Twitter.

— "Kirk Douglas loved tennis. He attended many tournaments and I knew him back when I was playing junior tennis in the 1950s. He was a talented actor who truly loved his craft. He loved his family even more. May he Rest In Peace," Billie Jean King, on Twitter.

— "Kirk Douglas was one of the biggest stars of all time & a brilliant actor with an unforgettable, blazing charisma. He will also be remembered for putting his career on the line by defying the Hollywood Blacklist, hiring writer Dalton Trumbo for the classic Spartacus," Mark Hamill, on Twitter.

— "RIP #KirkDouglas - a giant. One of a kind. A life most fully and extraordinarily lived. Sending condolences and love to Michael and family," Paul Reiser, on Twitter.