Gerard Butler and Jessica Biel
06/06/2011 at 07:00 AM EDT
Are Gerard Butler
and Jessica Biel
Their reps say the two actors are "just friends," but they appeared to be pretty close friends while shooting Playing the Field
in Shreveport, La., last month. And over the weekend, new photos surfaced of Biel enjoying a ride on the back of Butler's motorcycle down the PCH in Malibu.
A source in Shreveport tells PEOPLE that, off the set, Butler and Biel were "friendly but professional," but it's clear the two enjoyed each other's company in their downtime, as well.
Before shooting began, Butler, 41, who has a reputation as a ladies' man
, and Biel, 29, who had just broken up
with Justin Timberlake
, were the center of attention at a cast and crew dinner at Tokyo Japanese Restaurant. One source tells PEOPLE the two stars sat next to each other the entire evening, talking and laughing, with Butler eating off of Biel's plate.
"He knows he looks good," the onlooker tells PEOPLE. "If I were her, I'd hook up with him. She looks good, too, and she knew she looked good, swinging her hips around."
The source adds: "They looked like a couple. They were having a good time."
The two appear to have some things in common: both enjoy outdoor activities, with Butler using his time off the set to canoe while Biel played golf.
Butler especially endeared himself to the cast and crew, often going out of his way to talk with fans. Biel also was friendly, but a bit more reserved than Butler, who prefers the nickname "Gerry." The two seemed to strike up a genuine friendship while working on the movie, but most insiders insist they're nothing more than friends.
"Gerry has a large personality, and everyone, including Jessica, gets caught up in his world," one insider tells PEOPLE. "I think they enjoyed each other's company. It can be hard working on a movie, trying to establish a new routine, and it helps when you have someone with you to make you feel more normal."