MTO WORLD EXCLUSIVE: Rapper Lil Wayne . . . Is Reportedly CREEPING Around . . . With ENGAGED Singer Christina Milian!!!

: just got a CRAZY TIP. According to our snitch, rapper Lil Wayne has been CREEPING AROUND with pop singer CHRISTINA MILIAN . . . for the past TWO YEARS.

According to our insider, Christina and Wayne have HISTORY TOGETHER. The pair dated each other about 5 years ago – and have been seeing each other OFF AND ON ever since. The insider explained, “When [Lil Wayne] signed her to Young Money [in 2012] they were sort of seeing each other. Christina is very slick, so she made sure she got a CHECK out of their relationship, and she convinced him to sign her and give her a BIG ADVANCE.”

Christina and Wayne’s relationship began to fizzle out as Wayne got MORE INVOLVED with his then fiance DHEA and Christina got engages to her fiance JAS PRINCE – but the two always had FEELINGS for each other.

Now our snitch tells us that Wayne and Christina are BACK TO CREEPING AGAIN. The insider explained, “[Christina] was with him in Miami, and in Atlanta – she might say that they’re just friends. But Wayne doesn’t have any female ‘friends’ that he’s not f*cking.”

The two have something ELSE in common – their kids are STEP-SIBLINGS. You see Lil Wayne has a son with Nivea – who has kids by ex-husband THE DREAM – who has a daughter by Christina. Yeah, it’s complicated.