The 34-year-old actress revealed as much in an interview for the August issue of Harper's Bazaar. Portman is mother to four-year-old Aleph, and recalled how Blanchett reassured her after her son was born.
"Cate Blanchett is an amazing person," she lauded. "Very early on, I asked her about being a parent. I said, 'How do you do it? You're a mom. You're the best at what you do.' She said, 'You just do. Stressing about it doesn't help.'"
Portman and choreographer Benjamin Millepied welcomed Aleph in June 2011, and married in August 2012. Blanchett and husband Andrew Upton are parents to three sons, 13-year-old Dashiell, 11-year-old Roman and 7-year-old Ignatius, and an infant daughter, Edith.
"Children certainly teach one about compromise," Blanchett recently told Vogue Australia. "They are spirited, passionate, political and demanding. They constantly extend parents and so parents are constantly confronted with their failures ... I'd rather presently live life this way then not."
Portman and Blanchett will co-star with Christian Bale in The Knight of Cups and another upcoming Terrence Malick film. Portman is also scheduled for Jane Got a Gun with Ewan McGregor, while Blanchett will appear in Dan Rather biopic Truth with Robert Redford.