is turning 51 this month — and she's celebrating with the cover of Harper's Bazaar.

The actress fronts the , looking flawless in a fluffy pink princess dress by Giambattista Valli Haute Couture and a pair of Dior sneakers.

Inside, the Oscar winner is interviewed by , who quizzed her on her kids, social media, and why she took part in the Women's March after 's election.

Gorgeous! Julia Roberts, 50, covers the November issuer of Harper's Bazaar

Julia was shot by Alexi Lubomirski — the same photographer behind Prince Harry and Meghan Markle's engagement shoot — for the cover and fashion spread, in which she models evening gowns and athletic shoes while climbing on the side of a cliff.

She no doubt looks incredible, but Julia admitted she's read some nasty feedback about how well she's aging, and it hurt. 

Speaking to Oprah, she shared how shocked she was at the cruelty of people online, which she experienced firsthand after he niece, Emma Roberts, posted a snap of them together.

'One weekend morning Emma slept over, and we got up and were having tea and playing cards and having this beautiful morning, and then a couple of days later she posted a picture of us.

Girl talk: The star was interviewed by Oprah, and discussed her kids, social media, and the Women's March

Just mom: Julia, who scaled a cliff while wearing a very large ball gown for the shoot, said that her kids understand she's famous, but they don't really get how well-known she is

'And the number of people who felt absolutely required to talk about how terrible I looked in the picture — that I’m not aging well, that I look like a man, why would she even post a picture like this when I look that terrible! 

'And I was amazed at how that made me feel. I’m a 50-year-old woman and I know who I am, and still my feelings got hurt.

Julia also talked about her three kids, 13-year-old twins Hazel and Phinnaeus, and 11-year-old Henry, and said she doesn't think they'll ever have a 'true sense' of her being a superstar.

'I think I told you once when they were starting to figure it out,' she told Oprah. 'It was like, “You’re famous?”

'And I said, “I think a lot of people might have seen the movie that I’m in or might know who I am.” Maybe an hour goes by. “Are you more famous than Taylor Swift?”'

Family: She shared how shocked she was at the cruelty of people online, which she experienced firsthand after he niece, Emma Roberts, posted a snap of them together

Shocking: 'The number of people who felt absolutely required to talk about how terrible I looked in the picture,' she said. 'And I was amazed at how that made me feel'

Her kids may not understand that their mom is America's sweetheart, but that doesn't mean they aren't perceptive.

Julia said that her daughter Hazel was aware that her parents were pulling for Hillary Clinton in the last presidential election, so when Trump won, she felt it, too.

'When Donald Trump was elected, my daughter, Hazel, came down and the TV was on, and it said on the crawl at the bottom, Trump wins, and she kind of gasped because of course we all had this collective hope that something else was going to happen. 

'And what I saw in that exact moment was the complete need for me as a parent to find a way to make her feel that she could still have a voice. 

'That’s why we went to the first Women’s March in Washington — I wanted her to feel like she still had a place in the world, that she could still believe in what she believed in, even though someone else was now president. 

'It was very powerful for me to have her in a way be my leader into this space of marching and participating in being a citizen of this country.'