So it's not surprising that everyone is asking Stewart, 72, for her opinion on Blake Lively's new lifestyle company Preserve -- and true to Stewart's reputation, she's as candid as ever.
"Let her try," she tells HuffPost Entertainment about Lively attempting to become "the next Martha Stewart" a.k.a. the "mother of all how-to's."
"I don't mean that facetiously!" she explains, laughing off the obvious dis. "I mean, it's stupid, she could be an actress! Why would you want to be me if you could be an actress? I just did a movie yesterday, though -- I can't even tell you about it -- but I want to be Blake Lively."
Stewart is actually friends with Lively and her husband Ryan Reynolds, and also dishes about what the attractive couple are like in real life.
"They're very friendly, very nice people," she reveals. "In a way, kind of shy -- not shy on the screen, at all, if you've seen any of Blake's movies -- but very shy in person. But she's a baker and a homemaker and now she's starting her own blog [Preserve] ... I haven't seen it yet."
Lively herself talked about her friendship with Stewart in her recent Vogue interview.
"I've only ever found her to be completely generous and kind," the Gossip Girl actress, 26, said. "She's one of those people who connect people with each other. She's there for you."