In hard-to-believe news that has yet to be truly verified, Robert Pattinson is allegedly dating actress Riley Keough, who starred alongside his ex-girlfriend Kristen Stewart in the film 'The Runaways.'

Notice we said "allegedly."

So how did this rumor get started? Seems RPatz was seen with Keough -- who's Elvis Presley's granddaughter, by the way -- driving around in Rob's truck this past weekend. So in Hollywood gossip circles, that means they're basically already naming their babies.

The reportedly new couple were spotted with a ping-ping table in the back of Pattinson's truck -- the same truck he recently used to vacate Stewart's home -- as they headed to Rob's Los Angeles mansion.

Probably to have sex on that table, we would speculate if we wrote for a salacious tabloid.

For the record, Riley and Rob were already friends. They were photographed together back in April when they both attended KStew's birthday party -- but as for her friendship with Kristen? If the rumors are to be believed, Riley will now join Katy Perry on Stewart's ish list.