And while girlfriend K.Stew left an impression with her killer fashion choices, Rob has opted for talk of testicles to raise eyebrows. Yep, whereas he revealed Cosmopolis "gave him balls" earlier, he's now turned to talk about us actual, well, little Roberts.
That said, did K.Stew show up to support her boyfriend? And has Rob really been bashing Twilight while doing his promo rounds?
Of course she did! It's only fair after R.Pattz walked the On the Road carpet for her, after all!
Kristen upped the sex appeal (possibly to match the tone of the sexy thriller), choosing bright red for the red carpet, decking herself out in a lacey full-length gown with a plunging neckline and matching red lips.
Our favorite outfit of the week? Maybe! But more on that in a second...
As for the man on her arm?
Unfortunately, again, the Twilight twosome didn't walk together. Instead, Kristen was on the arm of one of Rob's best friends and her On the Road costar, Tom Sturridge (BTW, we're loving Tommy's ponytail thing lately!).
He did it up to the nines, with a fancy tux, slicked back 'do and adorably humble attitude. And he caused an appropriate amount of chaos for how good he looked, as fans went totally crazy when he arrived at the infamous Cannes stairs.
Though the film got mixed reviews, R.Pattz's mostly positive buzz should be a blessing for the actor formerly known only as Edward Cullen.
"Playing the same part for a while, you just run out of ideas," he recently told Shortlist about tiring of Twilight. "You feel kind of useless, you don't know what to do anymore. I kind of got to the end of my inspiration. You get to the point where you're like, 'I don't want to do a film for a teen audience any more'."
Well as long as Rob and Kristen keep stepping out to each other's premieres, we're OK with the impending end of the vampire franchise. We just want to see the couple looking fancy together, is that so much to ask?
And if we get another make out session after the Cosmopolis premiere, well, we won't complain about that either.