Observe this picture of Pop queen Madonna licking the side of Nas’ face. You can almost see the exact moment when he starts realizing what that tongue has done, where it’s been and how much soap and hand sanitizer he needs to correct the matter. But with millions of albums sold, “The Material Girl” can still provide any rapper with the proper crossover appeal—even at the ripe age of 56. She can keep those “Vogue” raps, but when it’s time for a mean 16 bars, she knows how to enlist the proper heavy hitters. Hit the jump and check out Madonna’s history of run-ins with rappers. - The Beastie Boys can attest to Madonna’s love of Hip-Hop. She brought the legendary trio on tour for her 1985 Like A Virgin Tour. - Madonna’s 2009 greatest hits album, Celebration, featured a Lil Wayne cameo on the track “Revolver.” That would be the first of her YMCMB collaborations for those of you keeping track at home. - The Chicago rapper was visited by Madonna backstage last year, and h