"One Fine Day was such a cornerstone for me, of who I am," Mae Whitman tells PEOPLE in this week's issue

Mae Whitman is opening up about some of her most memorable roles — and the special friendships she gained from them.

In this week's issue of PEOPLE, the Good Girls actress, 32, reflects on the 25th anniversary of One Fine Day — the 1996 romantic comedy in which she starred alongside George Clooney when she was just 8 years old — and the strong connection she's shared with the actor over the years.

"One Fine Day was such a cornerstone for me, of who I am," Whitman, who played Clooney and Michelle Pfeiffer's characters' daughter in the film, says. "Especially working with George, we became so genuinely close, in a way that is funny. He's just somebody that my soul really connected with."

mae whitman
Mae Whitman and George Clooney
| Credit: Getty

"I think we just had something that just felt natural and normal, and we had the same sense of humor," adds Whitman. "And he really took me under his wing, and he took me everywhere, all around New York. And for many, many years after I would go to his house and I would get chased by his pig Max across the yard!"

While Whitman kickstarted her career at just two years old, the Los Angeles native was able to maintain a semi-normal childhood ... and even had Clooney's help when it came to school projects.

"Remember when they used to sell wrapping paper in school, and you'd try to sell the most wrapping paper? I remember George would always wait until the very last day, like the deadline," she says. "And then he'd be like, 'Okay, what's the highest kid have?' And then he would quadruple it. So I would walk into class and go, 'George Clooney, he wants 10,000 wrapping papers.' Those are the memories I have. I felt so supported and I felt loved."

mae whitman and george clooney
Credit: Jamie Mccarthy/Getty; Rodin Eckeroth/Getty

Though Whitman has shared the screen with iconic actors such as Sandra Bullock, Will Smith and more, she's had the strongest connection with Clooney.

"These are people who are experts at their craft, guiding me and showing me the way, and being on set with me, and helping me in moments of vulnerability," the Parenthood actress says. "I just feel really grateful that I was able to have these experiences with these people I really respect, that are cornerstones of who I am now."

"[George] and I stayed close for many, many years," she adds. "I think one of the last times I saw him I was with an ex-boyfriend at a movie theater. I hadn't seen him in a while, and I went up and I was like, 'George, oh my God!' And he immediately bee-lined past me and grabbed the guy I was dating at the time, and was like, 'If you ever hurt her, I will hunt you down.' I feel like we will always have that connection."

Now, Whitman is gearing up for her fourth season as mom Annie Marks of NBC's Good Girls alongside Christina Hendrick and Retta.

"Like I truly don't even remember what my life was like before I knew them," Whitman says of her costars. "The thing I love about Good Girls is that everybody on the crew really cares so much. We really are like a big family, we really are so positive."

The latest season of Good Girls premieres March 7 on NBC.