Chelsea Clinton expecting her second child next summer

Chelsea Clinton is pregnant with her second child, the former first daughter revealed on Twitter on Monday.

Next summer, Charlotte is going to be a big sister! Feeling very blessed & grateful this holiday season. pic.twitter.com/gpCGqcmeCq

- Chelsea Clinton (@ChelseaClinton) December 21, 2015

Clinton's mom, Democratic presidential candidate Hillary Clinton, tweeted Monday that she and former President Bill Clinton are excited to welcome their second grandchild.

The former president tweeted that Christmas came early.

Clinton, 35, gave birth to her first child, Charlotte Clinton Mezvinsky, in September 2014. Clinton married Marc Mezvinsky in 2010.

Hillary Clinton frequently references her new title of grandmother on the campaign trail. In September, she said her granddaughter Charlotte can call her whatever she wants.

"I want to wait to see what she does call me," Clinton told ABC News. "Grandma's fine. Madame President's fine. Whatever she chooses."

Before the former secretary of state launched her 2016 presidential bid earlier this year, there was speculation that being a new grandmother would weigh heavily on her decision to run again.

  • Rebecca Shabad

    Rebecca Shabad is a video reporter for CBS News Digital.