The Twilight actor hosted a 34th birthday bash at his Los Feliz home for director Nicholas Jarecki and with a star-studded guest list that included 50 Shades of Grey author E L James.
Her best-selling trilogy about an S&M relationship between a student and businessman was partly inspired by the Twilight books and Rob's name has been buzzed about to play the title role of Christian Grey for quite awhile.
The fact that she attended a party at his house only adds fuel to the 50 Shades casting rumors fire.
The author wasn't the only bold faced name in attendance. Heather Graham, Ellen Page and even Warren Beatty also stopped by Rob's soiree, where Mexican food and ice cream cake was served.
One person who wasn't on the guest list was his former girlfriend Kristen Stewart. R. Pattz had "plenty of women around him but he didn't seem interested in anyone in particular," according to People.