Roberts, who is attending the 2009 festival for her movie "Lymelife," said she thoroughly enjoyed the laid-back feeling this year, Entertainment Weekly reported Saturday.
"I just love how relaxed it is here," she said of the event, which began Thursday and runs until next Sunday. "You're going to the premiere of your movie, and you can just wear jeans and a T-shirt."
Hennessy, Roberts' co-star in "Lymelife," agreed, saying those attending this year's Sundance festival appear to be more focused on the movies than on partying.
"People just seem intent on seeing the films and talking about independent movie-making," the "Crossing Jordan" star said.
Meanwhile, actor Kevin Bacon told Entertainment Weekly this year's event appeared to have less of a film distribution market compared with prior years.