They were both born to rock.

Fate brought Steven Tyler’s Aerosmith and Bruce Springsteen together to record their classic third albums side by side at the Record Plant in Midtown Manhattan.

That’s where the magic happened for Aerosmith’s “Toys in the Attic” and Springsteen’s “Born to Run” to turn both acts into rock royalty 50 years ago.

“We were locked into Studio A, and Bruce Springsteen was in the studio next to us, Studio B,” “Toys in the Attic” producer Jack Douglas exclusively told The Post.

“Jimmy Iovine was the engineer on ‘Born to Run,’ and he had been my assistant for a while,” he explained. “So Jimmy would frequently call me up while he was working [because] it was his first big project. He would ask advice about ‘What should I do with this? What should I do with that?’”

That led to some studio interaction between Tyler, now 77, and Springsteen, who were both signed to Columbia Records.

“Frequently we’d get a call from Jimmy: ‘Come on over and listen to what we’re doing over here,’” said Douglas. “And then we’d all pile in to listen to what Bruce was doing. And then we’d go, ‘Wow, that’s pretty good,’ and then we’d be inspired to kick it up a notch in Studio A.”

The inspiration went both ways for the future Rock & Roll Hall of Famers.

“Stevie [Van Zandt, Springsteen’s longtime guitarist] and Bruce might come over to us and that would kick them up a notch,” said Douglas. “And it went like that back and forth. We all got along.”

Columbia Records exec Bruce Lundvall would come to check in on the progress for both of his up-and-coming artists.

“Bruce played him some stuff, and then he came over and Aerosmith played him some stuff,” recalled Douglas. “And I walked him to the door, and he turned to me and said, ‘I think it’s gonna be a very good year for Columbia Records.’”

Indeed, it was in 1975. Aerosmith’s “Toys in the Attic” — featuring the classics “Walk This Way” and “Sweet Emotion” — would go on to become the band’s best-selling album, going nine-times platinum after its release on April 8, 1975.

Meanwhile, “Born to Run” — released later that year in August — would be the seminal LP that turned Springsteen, now 75, into the Boss as we know him.

“I was astounded by it,” said Douglas of the album that is widely considered Springsteen’s best work. “You know, I didn’t know Bruce at all, and hearing that stuff, it really struck a chord with me. It was totally different from what I was doing. But I just loved it.”

Looking back, he said that it was a meeting of rock gods for the ages: “We were making history on the ground floor of 321 West 44th.”