According to a source, the 24-year-old Kristen and Pattinson, 28, won't even look at one another at the fest, reports showbizspy.com.
"Kristen and Rob will not see each other at Cannes. Their films are screening far apart from each other," said a source.
Pattinson's "The Rover" and "Map to the Stars" are scheduled to be screened May 18 and May 19 respectively.
Stewart's "Clouds of Sils Maria" will open at the end of the festival around May 24.