JIM CAVIEZEL is “paying it backward” to Mel Gibson for giving him his first big break in Hollywood.

The “Person of Interest” star’s career took off after Mel chose him to play Jesus in his controversial 2004 film “The Passion of the Christ.” And now that the CBS thriller has turned into a runaway hit, Jim is lobbying producers to hire his mentor for a guest-starring role.

“Jim is a stand-up guy who’s never forgotten his roots,” a close friend told The ENQUIRER. “When Mel called a few months ago to congratulate him on the success of his show, Jim asked if he’d be interested in a guest role – and Mel said, ‘Sure!’

“So Jim has been huddled with producers, trying to figure out a way to weave Mel into the story line.”

In the series, Jim, 44, plays a former Special Forces soldier who sometimes metes out vigilante-style justice to take down bad guys.

Meanwhile, Mel’s career has been hampered by a series of scandals including a DUI arrest, an anti-Semitic rant, rehab for his chronic boozing, divorce from his long-suffering wife Robyn, and a love child with former girlfriend Oksana Grigorieva.

PLUS, there are shocking accusations of domestic violence and the infamous audio tape in which he berates and threatens Oksana.

But Jim isn’t holding Mel’s past against his old friend, reveals the source. And he’s hoping that a role on “Person of Interest” will endear Mel, 57, to a whole new legion of fans – and possibly win back some old ones.

Said the source: “It’s a win-win situation for both guys.”