Reese Witherspoon arrives at the 98th annual White House Correspondents' Association Dinner at the Washington Hilton on April 28, 2012 in Washington, DC. Credit: Paul Morigi/

Tennis matches, hikes, international travel, industry soirees--Reese Witherspoon certainly isn't letting her pregnancy slow her down!

In Cannes to promote her film Mud alongside costar Matthew McConaughey, Witherspoon opened up to Us Weekly about her trip--which involved a flight from Los Angeles.

"The flight over was actually pretty good. I feel great," she told Us Thursday. "I'm excited about showing the movie. The energy here is great!"

The This Means War actress, 36, and her hubby Jim Toth attended the Ciroc Vodka Erno Laszlo dinner for The Paperboy later that night, where Toth doted on his expectant spouse.

Witherspoon and Toth missed out on the main course, but nibbled on pastries for dessert, including strawberry tartlets, macarons and mini eclairs. "She and Jim were talking closely . . . he was clearly protective of her whenever they were standing up or walking around, practically putting both arms around her," a witness tells Us.

At one point, the actress and the CAA agent hung out with another American couple outside, where the partygoer says the mama-to-be assured her friends she was "surprisingly not tired." (Toth and Witherspoon ended up heading out around 11:15.)

"She was wearing a simple black dress and black jacket . . . She looked like she was more about comfort than being glamorous," the onlooker shares. "The baby bump is definitely taking shape now--Reese has a little waddle when she walks, which was cute!"