(CNN) Chelsea Clinton is out with the first photos of her new son, Aidan Clinton Mezvinsky.

"At 7:41 AM Saturday, our family and hearts expanded with Aidan's arrival. We are blessed," Chelsea Clinton tweeted late Sunday afternoon.

At 7:41 AM Saturday, our family and hearts expanded with Aidan's arrival. We are blessed. pic.twitter.com/QKUMV3ls4N — Chelsea Clinton (@ChelseaClinton) June 19, 2016

Her parents, former President Bill Clinton and 2016 presumptive Democratic presidential nominee Hillary Clinton, quickly followed with their own messages about the second child for Chelsea Clinton and her husband, Marc Mezvinsky. Aidan's sister, Charlotte Clinton Mezvinsky , was born in September 2014.

"What a joy being with our new grandson, Aidan. So grateful. -H," wrote Hillary Clinton, with "-H" a sign that the tweet was directly from her, not a staffer.

"Aidan has made two dads very happy this Father's Day. Hillary and I are thrilled for Marc and Chelsea!" Bill Clinton tweeted at about the same time.

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