George is the daughter of Law & Order: Criminal Intent star Vincent D'Onofrio and his ex-girlfriend, Greta Scacchi. Last month, she supported her father at the premiere of his movie, The Eyes of Tammy Faye.
Penn was previously married to Madonna from 1985 to 1989. He was also wed to Robin Wright from 1996 to 2010. The two actors share two children together; 30-year-old daughter Dylan and 28-year-old son Hopper.
ET recently chatted with Penn and his daughter about working together on Flag Day. The actor both directed and starred in the film, with both Dylan and Hopper acting as his character's children. Dylan said that while she enjoyed working with her dad, it was "intense."
"It does really feel like you're doing family therapy in front of a crew of strangers that eventually become your family," Dylan told ET at the Los Angeles premiere. "To be that vulnerable is scary, so to do it with your family around does help."
As for Penn, he hoped his daughter would join the project even if she had some hesitation.
"Dylan was so resistant, to the point of rebellious, about the notion of being involved in front of the camera. I was glad and excited when she accepted to do this," he told ET. "I gave her little nudges over the years, she had other nudges."