Bill and Hillary Clinton will get a grandchild next summer. Their daughter Chelsea is pregnant with her third child with her husband Marc Mezvinsky.

Clinton announced via Twitter that her four-year-old daughter Charlotte is a fantastic big sister for her two-year-old brother Aidan.

“We are looking forward to seeing Aidan become a big brother! We can not wait to meet our newest addition later this summer.”

Clinton and Mezvinsky were married in 2010. When the daughter of former President Bill and former presidential candidate Hillary is exactly calculated, is not known.