There has been wide speculation about a future baby in the Clinton family. Chelsea Clinton said in an interview with Glamour magazine last year that she and her husband were hoping to start a family soon, calling 2014 "the year of the baby."
"Marc and I are very excited that we have our first child arriving later this year and I certainly feel all the better whether it's a girl or a boy that she or he will grow up in a world with so many strong female leaders," Clinton said in New York, joined by her mother at a Clinton Foundation event on empowering women.
"I just hope I will be as good a mom to my child and hopefully children as my mom was to me," she said.
The former first lady, secretary of state and New York senator, who is considering another presidential campaign in 2016, said she was "really excited" about becoming a grandmother.
"It makes this work even more important because we've made a lot of progress," Clinton said. "I want to see us keep moving and certainly for future generations as well so that maybe our grandchild will not have to be worried about some of the things that young women and young men are worried about today."
She later added on Twitter: "My most exciting title yet: Grandmother-To-Be!"
The former president also expressed jubilation about the news on Twitter: "Excited to add a new line to my Twitter bio...grandfather-to-be! @HillaryClinton and I are so happy for Chelsea and Marc!"
Preparations for the new baby will coincide with Hillary Clinton's deliberations over another campaign for the White House. Mrs. Clinton is set to release a book about her time at the State Department in June, followed by a book tour, and Democrats hope she will be a top surrogate for their candidates in the 2014 midterm elections.
The former secretary of state is expected to announce her decision later this year and polls show her as the leading contender for the Democratic Party's nomination if she runs. If Clinton seeks the White House, her campaign would potentially coincide with her grandchild's first two years.
After growing up in the public eye as a teenager in the White House, Chelsea Clinton graduated from Stanford University and Columbia University's Mailman School of Public Health and worked in New York for a hedge fund and a management consulting firm.
She and Marc Mezvinsky, the son of two former members of Congress, were married in Rhinebeck, N.Y., in July 2010, and the former first daughter has balanced a number of work and interests, pursuing a doctorate from Oxford University, where her father was a Rhodes Scholar, while taking a leading role in her family's foundation.
She serves as vice chair of the family foundation, which was renamed the Bill, Hillary & Chelsea Clinton Foundation, and helps direct the organization's humanitarian and philanthropic efforts around the globe. She also serves as a special correspondent for NBC News.
She has avoided commenting on her mother's potential presidential campaign except to say that she'll support her in whatever she does. But she would be a strong voice for her mother among young voters if the former secretary of state decides to seek the presidency.