Summer blockbuster movies aren’t the only thing slated to arrive this summer: Former first daughter Chelsea Clinton will welcome Baby No. 3 later this year, she tweeted Tuesday.

Clinton and husband Marc Mezvinsky already have two children: Charlotte, 4, and Aidan, 2. “Marc and I have loved watching Charlotte be such a wonderful big sister and we’re excited to watch Aidan become a big brother!” she wrote. “We cannot wait to meet our newest addition later this summer.”

Clinton, 38, is the vice chair of her family’s Clinton Foundation and has written a number of books, including “She Persisted: 13 American Women Who Changed the World.” She and Mezvinsky, 41, a hedge funder, married in 2010.