Hillary Clinton Says Daughter Chelsea Will 'Always Be My Baby' in Throwback Birthday Post

Hillary Clinton shared a sweet black-and-white baby photo of daughter Chelsea Clinton to celebrate Chelsea’s 40th birthday on Thursday.

“No matter how much of a grown-up you become, you’ll always be my baby,” Mrs. Clinton wrote in a tweet with the photo. “Happy birthday, @ChelseaClinton.”

The photo shows the former first lady and secretary of state, now 72, with former President Bill Clinton, 73, holding Chelsea as a baby — both parents smiling and looking down at their young daughter.

Chelsea now has three children of her own: sons Jasper, who turns 1 year old later this year, and 3-year-old Aiden as well as daughter Charlotte, 5.

“We are overflowing with love and gratitude,” Chelsea wrote on Twitter soon after Jasper was born.

She married hedge-fund executive Marc Mezvinsky in July 2010.

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Chelsea told PEOPLE in a September 2015 interview that becoming a parent had changed her world and even boosted her love for her husband.

“I didn’t know I could care more intensely about anything until I became a mom,” she said then. “Somehow I love my husband even more, I love my parents even more. I feel even greater urgency about the work that I do, particularly around women and girls being a mom of a daughter.”

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In addition to her nonprofit and corporate work and role with the family’s Clinton Foundation, Chelsea is an author. Her books include Don’t Let Them Disappear, which teaches kids about endangered animals and “provides helpful tips on what we all can do to help prevent these animals from disappearing from our world entirely.”

Chelsea also wrote a book last year with her mom titled The Book of Gutsy Women, which explores stories of women in history showing confidence and courage.