So adorable!

Chelsea Clinton is desperately trying to help her one-year-old daughter, Charlotte, understand she is about to become a big sister — but the little one hasn't quite grasped the concept yet!

RELATED: "She’s Just So Cute!" Chelsea Clinton Gushes About Baby Charlotte — and Spills Details on Her 1st Birthday Party!

“I don’t think she has any idea what that means yet, but we’re talking about it a lot,” the 35-year-old former first daughter said while delivering a speech on Monday, Jan. 11, according to People. “She says ‘Baby,’ and then points to herself!”

https://twitter.com/ChelseaClinton/status/679038013138071552

The mom-of-one announced she and her husband, Marc Mezvinsky, are expecting their second child in December 2015. "Next summer, Charlotte is going to be a big sister!" she captioned an adorable snapshot of their little girl reading a book. "Feeling very blessed and grateful this holiday season."

RELATED: Chelsea Clinton Reveals Daughter Charlotte's First Word — Find Out What It Was!

Chelsea — who is the only daughter of Hilary and Bill Clinton — and Marc, 38, welcomed Charlotte in September 2014. The duo tied the knot in July 2010.

Click through the gallery below to see more cute celebrity kids!