Charlie Sheen’s pornstar fiancée has a thing for Robert De Niro ... so Charlie’s inviting him over for a smoking hot group session ... in his home photo booth.
Charlie just gushed over De Niro’s movie “Last Vegas” on Twitter ... and revealed he bought a photo booth used in the film -- probably because his bride-to-be Brett Rossi is Bobby D's "biggest fan."
Now, in a move only Charlie Sheen could pull off -- he's SERIOUSLY asking De Niro to drop by his house to take a few selfies with Brett in the booth.
It's a pretty decent proposal ... considering De Niro's done worse.
Grudge Match, Little Fockers, New Year's Eve ...