08/13/2010 at 02:33 PM EDT
Maybe Pretty Woman should moonlight as a dog whisperer.
When Julia Roberts
recently stopped by the Late Show with David Letterman
to promote Eat Pray Love
, the visit turned into behavioral consultation for the late-night host's dog, a rambunctious 3-month-old yellow Labrador named Sully.
"I have a lot of dog trouble," Letterman said. "All he wants to do is shred our flesh and drink our blood."
The Oscar winner had a less dramatic experience while raising her own Lab, Louie
, who was a 2004 wedding gift from her husband, Danny Moder. Back then, the cameraman explained that their playful pup could one day grow into a huge handful, prompting Roberts to "teach Louie some manners."
"Little 23-lb. Louie, eight and a half years ago, he came into my arms," she said. "Now he's 100 lbs. He's a great dog. He's awesome."
Letterman's Sully is another story. "We're pulling for this dog. We want this dog to be a beloved member of the family. We're trying to reward good behavior," he said. However: "When the trainer leaves, it's a hell dog."
"Maybe it's not the dog, " Roberts suggested. "You need to be trained!"Read more stories about celebrities and their pets on PEOPLEPets.com:Josh Brolin: My Dog Milo 'Looks Exactly Like Me' Carrie Underwood's Wedding Kiss Stressed Ace Out!