The 61-year-old Oscar-winner died after the small aircraft he was piloting crashed in Santa Barbara, California, and his loss has sent a shockwave through the movie industry.

Crowe and Howard both worked with Horner on 2001 drama A Beautiful Mind, which earned the composer an Oscar nomination, and the actor wrote in a post on Twitter.com, "My sincere condolences to the family, loved ones and friends of James Horner. #abeautifulmind," while his director added, "Brilliant Composer James Horner, friend & collaborator on 7 movies has tragically died in a plane crash. My heart aches for his loved ones."

Howard also worked with Horner on films including Willow, Cocoon and Tom Hanks' Apollo 13.

As well as Apollo 13, Horner also provided the music for Hanks' 1985 movie Volunteers, which the actor starred in along with his wife Rita Wilson, who tweeted, "James Horner composed the score to Volunteers, the movie that @tomhanks & I did in 1985. Beautiful score. Prayers 4 (for) James and his family."

Funnyman Seth MACFarlane added, "Incredibly saddened to hear about the loss of James Horner. I grew up loving his work. He leaves behind a spectacular musical legacy" while actor Rob Lowe wrote, "There is nothing that shaped my movie-going experience more than the musical genius of James Horner. He will live on through the ages."

Other stars to add tributes include Jamie Bell, Kirstie Alley, Ron Perlman, Josh Groban and OneRepublic.