July 22 (UPI) -- Chelsea Clinton is a mom of three.
The 39-year-old author, global health advocate and former first daughter took to Twitter Monday after welcoming a baby boy, Jasper, with husband Mark Mezvinsky.
Clinton and Mezvinsky are also parents to 4-year-old daughter and 3-year-old son Aidan. Clinton said she's looking forward to baby Jasper meeting his older siblings.
"This morning we welcomed our son, Jasper Clinton Mezvinsky. We are overflowing with love and gratitude and can't wait to introduce him to his big sister and brother," she wrote.
"Sharing some happy news this morning! Bill and I are so thrilled," she wrote.
Clinton had announced her pregnancy on Twitter in January.
"Marc and I have loved watching Charlotte be such a wonderful big sister and we're excited to watch Aidan become a big brother! We cannot wait to meet our newest addition later this summer," she wrote.
Clinton is a board member at the Clinton Foundation and the Clinton Global Initiative. She has written five children's books, including Don't Let Them Disappear: 12 Endangered Species Across the Globe, which was published in April.