Are they or aren't they?!

We caught Rob Pattinson driving around his truck with a mystery girl yesterday, and now that we've identified her as Elvis' granddaughter Riley Keough, we have to wonder whether the gorgeous redhead is dating the Twilight hottie?

This isn't the first time the two have hung out, either!

The 24-year-old hung with the British hunk at K-Stew's birthday bash at Malo in Los Feliz on April 9. The On The Road actress and Keough co-starred in The Runaways together, and we highly doubt Kristen would have invited Riley to her birthday if they weren't friends, so maybe her pal hanging with her former man is a sign that Robsten is back on?!

We're thinking Kristen sent Riley to convince Rob to give their relationship yet another go!