Anne Hathaway does her best to not be too hard on herself when work gets in the way of spending time with her son Jonathan Rosebanks, 2½

Stepping into the minds of characters can be tricky, especially when you have a young son to care for.

“I’m learning. It’s a new set of muscles,” Anne Hathaway says of motherhood in her PEOPLE cover story this week, excerpted from the latest installment of The Jess Cagle Interview (streaming now on PeopleTV), hosted by Editorial Director Jess Cagle.

The Academy Award-winning actress, 36, shares son Jonathan Rosebanks, 2½, with husband Adam Shulman.

“It’s hard when you play characters that are isolated,” she explains. “I just did one this summer. My God, she was such an island, and it’s a little harder because I’d be holding [Jonathan], but I felt like I wasn’t really giving it to him.”

ALBERTO E. RODRIGUEZ/GETTY

And although it can be easy as a mother to criticize yourself regarding your availability for your children, Hathaway explains, “I try to be nice to myself.”

“I’m not big on mommy guilt. I just don’t really do it unless I really, really, really, really, really need to,” she adds.

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While she’s shooting a movie, the actress also emphasizes that it’s important not to let the character she’s playing seep into her home life.

“If I’m in a character for three months, I make sure that I’m not in character for three months,” she adds. “That way I’m never asking for him to share me for too long.”

The Serenity star went on to reveal that when it comes to taking on difficult roles, she just reminds herself that she won’t be in that headspace for forever.

“With that one, I just say to myself, ‘It’s three months. It’s three months and you’re doing your best,’ ” she shares. “The way I counteract is to the best of my ability.”

Anne Hathaway. HAN MYUNG-GU/WIREIMAGE

Admitting that this is “just what life’s going to be” until her son grows up, Hathaway adds, “I just want to figure out how to become nimble at it. I don’t know if I’m that nimble at it yet.”

However, the Les Misérables actress and singer still has a few more years to perfect her ability to not bring her work home with her.

“Now it’s a lot easier. I can just stick my hand in a puppet and [it] doesn’t matter who’s talking,” she quips, adding that “as [Jonathan] gets older,” things will probably become more difficult.

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Last week, Hathaway revealed that until her son moves out on his own, she’s going to abstain from imbibing alcohol.

During an appearance on The Ellen DeGeneres Show, the star admitted she doesn’t “totally love the way” she drinks, explaining that Jonathan is “getting to an age where he really does need me all the time, in the mornings.”

“I did one school run one day where I dropped him off at school — I wasn’t driving, but I was hungover,” The Princess Diaries star recalled. “That was enough for me. I didn’t love that [experience].”