The 89-year-old movie legend died after suffering a stroke at her home in Manhattan, New York.
Caan, who worked with Bacall in 1990's Misery, shared his sorrow in a statement to Entertainment Weekly which reads, "She was a great, uplifting lady who was full of talent and fun. I feel fortunate to have had the opportunity to work with her. I will miss her dearly."
Barbra Streisand, who directed Bacall in The Mirror Has Two Faces, says to Billboard.com, "What a terrible loss for us all... It was my privilege to have known her, to have acted with her, and to have directed her... And, most of all, to have had her as a wise and loving friend. She was an original. Even with all those great films we can visit again and again, she will be missed."
Alec Baldwin writes on Twitter.com, "The great Betty Bacall (her birth name) is gone. Read her first autobiography, By Myself. I love that book," while Kiss rocker Gene Simmons adds, "Lauren Bacall - sad. R.I.P. She was a class act. She will be missed."
Alan Cumming uploaded a picture of himself with the late actress and writes, "You are a sensation and a killer! (First thing Bb ever said to me) RIP Betty you sensational killer," and Richard E. Grant adds, "Worked with Lauren 'Betty' Bacall who called herself a 'Broad'.Took no prisoners, but if she liked you, you were friends for life. Unique."
Other stars have sent their condolences via social media, including John Cusack, Stephen Merchant, Belinda Carlisle, Boy George, Dita Von Teese and Lynda Carter.