”American Idol” creator Simon Fuller (Matt Sayles/AP)

In his breach-of-contract suit against Fox and FremantleMedia North America, “American Idol” creator Simon Fuller claims that they have reneged on a promise to give him an executive-producer credit and salary on the upcoming “The X Factor” — the “American Idol” knockoff — to snooker him into dropping a copyright-infringement suit against the newer show.

The dirty work, the suit says, just goes to show that Fox “and ultimately its parent company, News Corporation, have demonstrated a callous disregard for Fuller’s rights which, given recent developments, reflects a corporate culture — if not a pattern of practice — of wrongful behavior,” Fuller’s suit says.

The lawsuit, filed in Los Angeles Superior Court, claims that Fuller negotiated an exec-producer credit — and an exec-producer salary — on “X Factor.” The suit says those were negotiated as part of a settlement of a 2004 copyright-infringement lawsuit against “Idol” judge Cowell — as suit filed after Cowell launched “X Factor” in the UK.

An American version of “X Factor” — exec-produced by, and starring, Cowell — is set to debut in September on Fox. Fuller contends that FremantleMedia North America — which produces both singing-competition series — and Fox have refused to honor their deal with him on that new series.

“Mr. Fuller has prudently attempted to settle this matter privately, but the other parties have refused to honor the original contact, leaving him no other choice but to pursue legal action,” Fuller’s rep said Thursday.

Simon Cowell will judge “The X Factor” (Ian Derry /FOX)

By 2005 — when “American Idol” was Fox’s most valuable TV asset and the most watched program in the United States — Fox had locked up rights to broadcast “X Factor” in this country as the network stepped in to broker a deal between the two parties. That’s because, Fuller said, Fox feared that Fuller’s lawsuit against Cowell “could have ruinous effect” on “American Idol.”

In the bury-the-hatchet deal brokered by Fox, the network and FremantleMedia North America “contractually promised” to give Fuller an exec-producer credit and an exec-producer fee on the U.S. version of “X Factor” — a fee that would be “commensurate with his duties and stature in the entertainment industry,” Fuller claims.

“Fuller settled his litigation in reliance upon these promises,” the suit adds.

(The suit also says that the parties, in settling, agreed that “X Factor” would not come to the United States until 2011; that Cowell would remain as a judge on “American Idol” at least from 2005 until 2010 — he left the show in the spring of ’10; and that Fuller would be given a minority interest in the “X Factor.”)

“Now, when it is time to finally perform on these unequivocal promises, Fox and Fremantle refuse to provide Fuller with his executive producer credit [on] ‘X Factor,’ and refuse to pay Fuller an executive producer fee ‘commensurate with his duties and stature in the entertainment industry,’ ” Fuller’s complaint says.

For good measure, it throws in: “Defendants’ refusal to honor their promises made to Fuller is particularly malicious given that but for Fuller’s agreement, the ‘X Factor’ show would not be able to be broadcast in the United States at all.”

In a statement issued to the media, FremantleMedia North America and Fox Broadcasting Company said, jointly:

“Mr. Fuller has not been hired, nor performed any duties, on the U.S. version of ‘The X Factor.’ His suit seeks payment and credit as an executive producer despite his neither having been approved by the required parties, nor hired, as such. We believe this lawsuit is without merit and we expect to prevail.”