Chelsea Clinton announced Saturday morning that she has given birth to her second child: a boy named Aidan Clinton Mezvinsky.
Clinton, 36, made the announcement on social media.
In a statement, former President Clinton and Hillary Clinton, the presumptive Democratic presidential nominee, said they were "overjoyed to be grandparents again."
"We are all over the moon as Chelsea and Marc welcome Charlotte's little brother to the world and grateful for our many blessings," the Clintons said. "Chelsea and Aidan are both doing well and enjoying this very special time together."
Chelsea Clinton gave birth to her daughter Charlotte in September 2014, well before Hillary Clinton announced her 2016 presidential run.
Chelsea Clinton has frequently appeared on the campaign trail for her mother this year, holding organizing events for her mother's campaign across the country.
Chelsea Clinton was born on Feb. 27, 1980, in Little Rock, Arkansas, and she moved into the White House on the day of Mr. Clinton's first inauguration on Jan. 20, 1993, when she was 12 years old.