"He actually stopped production and was there for me," Jackson, 43, told PEOPLE on Monday at the New York premiere of Perry's new film, Why Did I Get Married Too? "[He was] constantly calling me, making sure I was OK, making sure that there wasn't anything that I needed or my family needed."
He is "such a sweetheart," she added, "so giving and so loving."
Perry, 40, asked Jackson if she wanted to take a few weeks off, but in the end she returned to the Bahamas set the day after Michael's funeral. "Once I spoke to her and found out that she was at a place of strength and going to be with her family, I felt safe enough to know that she was going to be OK," he told PEOPLE.
Finishing the film, Perry added, might have been the best thing for Jackson. "I think that a lot of times, people are not able to release," he said. "They don't have a way to let go. And that's the great thing about having a film like this, where she got to do all of these crazy things. And I think all of [her] emotion is in the film, I really do."
At one point in the movie, Jackson's character smashes up furniture with a golf club. She told Jay Leno on The Tonight Show last week that it wasn't too difficult to channel those kinds of powerful emotions.
"You have to dig deep," she said. "But there was some stuff that was right there for me – stuff that had just happened, with my brother passing, and also relationships."