Robert Pattinson NEVER Dated Riley Keough [VIDEO]: Lisa Marie Presley Debunks Rumors, Elvis Presley's Granddaughter and Kristen Stewart 'Best Friends'

Back in July, Robert Pattinson allegedly "romanced" a mysterious redhead following his split from "Twilight" sweetheart Kristen Stewart. Several gossip outlets later identified that young woman as Elvis Presley's granddaughter, Riley Keough. But according to Keough's mom Lisa Marie Presley, such dating rumors are a complete lie. Keough's really good friends with K-Stew... she'd never do such a thing!

If Mstars fans missed it:

Robert Pattinson NOT Dating Riley Keough? Kristen Stewart's Ex Spotted Riding with 'Mystery Redhead,' R-Patz 'Wants Non-Cheating Girlfriend'

Kristen Stewart 'Confronts' Robert Pattinson's New Girlfriend Riley Keough? 'Twilight' Starlet Deems Hookup 'Really Uncool,' Runaways Co-Star Doesn't Want Drama

Robert Pattinson, Kristen Stewart Split Prompts 'Playboy' Status? [PHOTOS]: Dates Riley Keough, Parties with Michelle Rodriguez, Flirts with Sia Furler at Jay-Z Concert

But forget all the rumors! Keough's own mom set things straight on Thursday's episode of "Watch What Happens Live" (Oct. 17). After a Bravo fan calls to ask about Riley's dating life, Presley responds:

"I will say who she's not with... and that is a complete lie, and the silliest thing I've ever heard, is that she was with Robert Pattinson, because she and Kristen Stewart are like best friends. So that was the craziest rumor that I will put to bed... That was NOT true." 

Check it out:

FYI - Stewart and Keough starred together in the all-girl rock band film "The Runaways."