His son, singer Robin Thicke, shared this message on Instagram.
Thicke's first wife Gloria Loring, Robin Thicke's mother, expressed her grief on Facebook.
His former daughter-in-law, Paula Patton, shared a quote from Mother Teresa.
Thicke will be deeply missed and here's how other celebrities reacted to his death.
So sad is the passing of Alan Thicke. Such a good husband, father, brother, and friend. He will be deeply missed. Rest in peace dear Alan.— bob saget (@bobsaget) December 14, 2016
Alan Thicke was always the nicest and happiest person in the room. Gone way too soon. Rest In Peace.— Alyssa Milano (@Alyssa_Milano) December 14, 2016
I'm shocked to hear about Allan Thicke. He was a good man who gave me some big breaks in my early days. I'll miss you buddy.— Howie Mandel (@howiemandel) December 14, 2016
Saddened over the loss of my friend Alan. Condolences to his family.— William Shatner (@WilliamShatner) December 14, 2016
America loved Alan Thicke. I'm so sad he's gone. Sending so much love to his family.— Ellen DeGeneres (@TheEllenShow) December 14, 2016
I'm so sad to hear about the passing of Alan Thicke. RIP Alan. 😢— Lori Loughlin (@LoriLoughlin) December 14, 2016
The NHL family is sad to learn of the passing of longtime hockey fan Alan Thicke. Our thoughts are with his family and friends. pic.twitter.com/5ADyWRksuf— NHL (@NHL) December 14, 2016
I'm sad beyond words that Alan Thicke has passed away. I've known you since I was 8 years old… https://t.co/GLXSTK1nd7— Candace Cameron Bure (@candacecbure) December 14, 2016
Had the pleasure of meeting Alan Thicke and his amazing wife Tanya a few years back.. my thoughts and prayers are with his family. RIP 😔— Demi Lovato (@ddlovato) December 14, 2016
So sorry to hear of the passing of Alan Thicke. A wonderful talent, a wonderful man. https://t.co/tb50aiVzlR— Larry King (@kingsthings) December 14, 2016
To my @WifeSwap partner...I'll miss you. RIP Alan Thicke— Gilbert Gottfried (@RealGilbert) December 14, 2016
RIP to my brother Alan Thicke. The world has lost an icon. 🙏🏾 pic.twitter.com/zIK0hzjihK— Russell Simmons (@UncleRUSH) December 14, 2016
Condolences to the family of @Alan_Thicke. If ever there was a time celebs are thinking about our mortality, 2016 is it.— Chaka Khan (@ChakaKhan) December 14, 2016
My heart goes out to Alan Thicke's family. Such a kind man. Saw him recently. Life is fragile. May he rest in peace. Praying for his family. pic.twitter.com/lcAVEu1KWL— Maria Shriver (@mariashriver) December 14, 2016
Rest in peace Alan Thicke - You brought so much light, love and humor to the world! Deeply grateful for your friendship and wisdom.— Ed Helms (@edhelms) December 14, 2016
RIP Alan Thicke who was a great talent and a genuine person. #everyonesdad— Dane Cook (@DaneCook) December 14, 2016
Sorry to hear of the passing of Alan Thicke, he was always cool and generous with his advice towards me...my condolences to the family— mark mcgrath (@mark_mcgrath) December 14, 2016
RIP Alan Thicke. I grew up watching him and got to know him through Robin. He was always so kind to me. So sad to hear about his passing.— John Legend (@johnlegend) December 14, 2016
Alan Thicke was one of the nicest guys in our business. And he LOVED his family. And hockey. A shocking, sad loss.— Rob Lowe (@RobLowe) December 14, 2016