Chelsea Clinton has given birth to a baby girl named Charlotte.
The 34-year-old, whose husband is investment banker Marc Mezvinsky, tweeted the news to her 624,000 followers.
Marc and I are full of love, awe and gratitude as we celebrate the birth of our daughter, Charlotte Clinton Mezvinsky.
- Chelsea Clinton (@ChelseaClinton) September 27, 2014
The baby is the first grandchild of Bill and Hillary Clinton, who have told about their excitement at a number of public speaking events in the past few months.
News of the birth - four days before the expected due date - will come as welcome news to Hillary supporters who want her to run for president because she has said she would wait until she became a grandmother before launching a second bid for the nomination.
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On Tuesday Chelsea, the Clintons' only child, appeared on CNN with her growing baby bump as she revealed they had decided not to find out the gender of their first child until the birth as they wanted it to be a surprise. She said: "There are so few mysteries in life...any answer is a happy one.
"So my husband and I decided that we would enjoy this mystery for the nine-plus months that we're granted, and we are eager to find out what God will have given us."
The name Charlotte dates back to the 1700s and, according to our Baby Names Generator, is the 'feminine variant of Charles, meaning manly'.
The couple, who got married in July 2010, announced that they were expecting their first child in April.
She said at the time: "I just hope that I will be as good a mom to my child and hopefully children as my mom was to me."