Machine Gun Kelly ’s been talking all things co-parenting with ex Megan Fox ... but fans are dying to know -- what’s the deal with him and Sydney Sweeney ?!

The rapper popped up on "Watch What Happens Live" Sunday night, where Andy Cohen threw a fan question from Kyle P his way, asking if he and Sydney were more than just friends. MGK’s response? Pure comedy, as always! Page Six

MGK straight-up told Kyle P to "shut up, dude," and the entire audience lost it. And ... that was the end of that.

The question definitely felt like a nod to Sydney’s partying session with MGK back in May , right after her split from fiancé Jonathan Davino -- so it’s not like the ask came out of nowhere. Instagram/@sydney_sweeney

And if you dig deeper into it, MGK didn’t ac

See Full Page