Chelsea Clinton announced she and her husband were expecting their first child Thursday afternoon during a New York discussion for girls on Thursday afternoon.

The forum, titled "Girls: A No Ceilings Conversation," was streamed live from the Lower Eastside Girls Club on the Clinton Foundation website. It was co-hosted by Clinton and her mother, Hillary.

Clinton, the daughter of former President Bill Clinton and former Secretary of State Hillary Clinton, married her husband, Marc Mezvinsky in 2010.

Clinton, 34, told the group she had "one more thing to say" after the 90-minute forum, thanking all the participants for "inspiring" her.

"Marc and I are very excited that we have our first child arriving later this year," she said to a lot of applause. "I just hope that I will be as good a mom to my child, and hopefully children, as my mom was to me."

Her mother beamed as Clinton made the announcement and said she was "really excited about" her future grandchild.

Clinton took to Twitter shortly after. She had more than 700 retweets within a half hour.

"Marc and I are so thrilled to be expecting our first child in the fall! Thank you for all of the kind words!" Clinton tweeted.

(Alison Fox)