Robert Pattinson's latest film -- Cosmopolis -- doesn't premiere at the Cannes Film Festival until Friday, but the actor headed to the seaside festival early to support his girlfriend Kristen Stewart -- whose film On the Road premiered Wednesday. It marks a rare non-Twilight related public appearance for the famously private couple, who have never publicly acknowledged their romance and habitually dodge questions on the subject.

Pattinson's appearance was a welcome surprise for gawkers still reeling from Angelina Jolie's no-show at Brad Pitt's Killing Them Softly premiere. Overheated fans shrieked in excitement when Pattinson arrived, and the actor happily posed for photographs before making a swift beeline for the famous red steps leading to the March du Film theater.

Stewart arrived nearly 30 minutes later, surrounded by security in a 50's style car. Known for her low-key red carpet treatment, Stewart wore minimal makeup and kept her hair natural and unstyled. Her sultry yet tasteful floral gown by Balenciaga is definitely a Cannes fashion highlight.

Directed by Walter Salles, On the Road is a compelling adaptation of the 1957 Jack Kerouac novel. Stewart's performance as the vivacious and sexually uninhibited Marylou is earning early critical accolades.

Will K-Stew show the same support for Pattinson during the Cosmopolis premiere? Robsten fans will have to wait until Friday's screening of David Cronenberg's latest to find out.