Howard helmed fantasy classic Willow in 1998, and took his adventure movie to the revered French movie event, only for critics to turn on his work after a cringe-worthy screening.
However Eastwood - who was in the audience - turned the reaction around by giving the film a rapturous applause.
And Howard's daughter Bryce insists the kindly Dirty Harry star didn't disappoint her when she arrived to start work on his latest movie.
She tells Britain's You magazine, "The night before shooting I was terrified because I had auditioned on tape and I didn't meet Clint until five minutes before we started filming. But he was really great. He makes an effort to be kind to everyone.
"My dad made a film called Willow when he was a young filmmaker, which he screened at the Cannes Film Festival and people were booing afterwards. It was so painful for him and Clint Eastwood, who he didn't know at that time, stood up and gave him a standing ovation and then everyone else stood up because Clint did. He puts himself out there for people."