Sean "P. Diddy" Combs is taking a legal hit over his biggest hit.

The hip-hop honcho is being sued for allegedly cheating his co-writers out of big bucks from his smash "I'll Be Missing You." 

In a $4 million suit filed in Manhattan Supreme Court, Universal-MCA Music Publishing charges the "Mo' Money, Mo' Problems" rapper and his company, Bad Boy Records, conspired to rip off three of their writers on his 1997 CD "No Way Out." 

The trio — Todd Gaither, Kelly Price and Jeremy Graham — co-wrote six of the songs on the album, including Combs' number one hit, "I'll Be Missing You," a tribute to his slain rapper pal Biggie Smalls based on the Police song "Every Breath You Take." 

While the album has sold more than 5 million copies, the suit charges the writers have gotten zippo in royalties because of the "fraudulent activities" by Combs and Bad Boy. 

Specifically, the suit charges the recording agreement Combs struck with his company is a sham designed to keep cash out of the writers' pockets, because it places a cap on the amount of royalties paid out on songs written or co-written by Combs. 

The Bad Boy agreement says the cap has already been exceeded so the writers get nothing. 

Combs' spokeswoman, Nathalie Moar, countered that "this lawsuit has no merit whatsoever."

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