Lawrence, an Oscar winner and considered a top star, is getting an exceptional $20 million against 30 percent of the profit after the movie breaks even, say sources. Sony declined to comment.

Whatever the famously fiscally prudent Rothman’s misgivings might have been about paying such big bucks to talent or risking $150 million ($120 million with production incentives) on an original script that has floated around Hollywood for years, he now finds himself in possession of a two-hander star vehicle with the most in-demand male and female actors in the business.

Passengers is set to begin filming in September so Sony has been under pressure to act. Sources say Rothman wrestled with whether to greenlight it, put it in turnaround or place it with Jeff Robinov’s nascent Studio 8, which is partly owned by Sony and will distribute its films through the studio but has outside financial backing.

Passengers was awaiting his green light — rich deals in place — when he took the top job at Sony’s film studio in late February after Amy Pascal stepped down. In early June, Rothman made a pitch to Tyldum to trim the budget to $90 million, only to be met with stiff resistance. A source with knowledge of events says agreeing to a project at this budget “was a violation of the way [Rothman] likes to put together movies.”

Producer Neal Moritz had other options: The project generated strong interest from Warner Bros. and Universal (the latter studio swooped in last year to grab Danny Boyle’s Jobs after Sony balked at the price tag).

Rothman — who was heard wondering aloud during deliberations about the actual star power of Lawrence, 24, and Pratt, 35 — solicited input from Robinov, who is looking to assemble his own slate of films. After a June 5 meeting with Tyldum, Robinov is said to have immediately offered to take on the project — which one source says could be sold as “Gravity with romance” — at the full budget. Making the ready-to-go film would have allowed Studio 8 to release a high-profile project much faster than it would be able to do through the laborious development process.

Rothman, 60, had told the filmmakers they could take the movie elsewhere if they chose, but when they chose the Studio 8 option, he is said to have changed his mind.

Rothman is hedging his bet on Passengers: Sources say he has secured financing partners Village Roadshow and LStar to cover as much as 75 percent of the budget.

One source says Rothman found himself in a potential “lose-lose scenario” because he was caught between placing a big wager on untested material — and setting a pay precedent that might haunt him in his new role — and passing on a project with two of the biggest stars in Hollywood. He also could have sat on the project long enough that the stars would have had to move on to other commitments, which would have angered three talent agencies because Lawrence is with CAA, Pratt is at UTA and Tyldum is with WME.

Passengers bounced from place to place before landing at Sony Pictures. At one time, when it was a Weinstein Co. project with Keanu Reeves and Reese Witherspoon, it was budgeted at a modest $35 million. Recently, Rachel McAdams was attached to the project. Ironically, for a time the project was in negotiations for a deal at Warner Bros., where Robinov had been chairman of the film studio — with the budget capped at $65 million.