"I'd make anything with Eddie," Ratner said in an exclusive interview with TheWrap, declining to offer specifics on the project.
The project is not the widely reported "Beverly Hills Cop 4," Ratner said, though the director told TheWrap he'd still like to make that one day.
On the weekend in which Ratner's latest project with Murphy, the Universal-Relativity caper comedy "Tower Heist," opened to a disappointing $25 million, the filmmaker said he was nonetheless "ecstatic" about the box office result.
"A $25 million opening is nothing to complain about, and I think it's excellent in a market that is obviously soft," he said, adding that audiences increased from Friday night to Saturday night.
"It's been a great experience," Ratner said. "He's come out and really supported the film. What I'm excited about is, we just have a great collaboration ... I really love working with him. To me, he's my hero."
He seems to mean it.
Ratner, who is producing next year's Academy Awards, has brought Murphy on to host the show. And Murphy -- or at least his voice -- stars in Ratner's upcoming animated film "Hong Kong Phooey."
Ratner said that Murphy was instrumental in his directing career -- even if the actor didn't know it.
"'Rush Hour' wouldn't have existed if it wasn't for Eddie, because I studied his movies," Ratner said. "No one did an action comedy better than him."
In "Tower Heist," the director said he particularly enjoyed watching the actor return to the sort of "street role" he played early in his career.
"We didn't see him do a street character in so long," he said. "He just hasn't played that street character ... He chose to do some different types of movies which are kind of family movies."
And he said the movie, about working people who try to recover money they lost to a Wall Street billionaire's ponzi scheme, wasn't meant to make any statement.
"It's nice to make a movie that's about something or is in the zeitgeist," he said. "But really, we set out ... to make a fun movie that was entertaining. We weren't trying to pound in some kind of message in there."