John Mellencamp and Meg Ryan: Secretly Dating

Recently separated rocker hooks up with movie star

Credit: Jeffrey Ufberg/WireImage (Mellencamp), Ray Tamarra/Getty (Ryan)

"A little ditty 'bout John and Ryan…"

Rocker John "Cougar" Mellencamp and actress Meg Ryan, 49, are collaborating…on a romance.

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"They are indeed dating," a source tells the new issue of Us Weekly (on stands Wednesday). According to the insider, Mellencamp and the Sleepless in Seattle star were first spotted together in NYC in October.

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Though Mellencamp, 59, recently called it quits with Elaine Irwin Mellencamp, his wife of 18 years, a source tells Us that "Meg came into the picture much later — well after they decided to split."