This will be the first time the group, which has been mired in controversy since a series of videos by anti-abortion activists were released in 2015, will endorse in a presidential primary.
"As a lifelong Planned Parenthood supporter, I'm honored to have the endorsement of the Planned Parenthood Action Fund," Clinton said in response to the endorsement. "There has never been a more important election when it comes to women's health and reproductive rights -- and Planned Parenthood's patients, providers, and advocates across the country are a crucial line of defense against the dangerous agenda being advanced by every Republican candidate for president."
The group will make the endorsement official at what they are billing as their election kickoff event in Manchester, New Hampshire on Sunday. The group plans to spend at least $20 million in this election cycle, according to a press release.
The endorsement was somewhat of a forgone conclusion. Clinton regularly mentions Planned Parenthood on the campaign trail -- "I will defend a woman's right to choose," she says -- a line that draws applause from Democratic crowds.
"In Congress and on the campaign trail, Republicans that claim they just hate big government are only too happy to have government step in when it comes to women's bodies and heath," Clinton said at the New Hampshire Democratic Party's Jefferson-Jackson Dinner in 2015. "It is wrong, and we are not going to stand for it."
Planned Parenthood's endorsement, which was first reported by CBS, is sure to draw scorn from Republican presidential candidates, many of whom regularly pledge to defund the group is elected president.
In accepting the endorsement, Clinton said the United States needs "a president who has what it takes to stop Republicans from defunding Planned Parenthood and taking away a woman's right to basic health care."
"If I'm elected," she added, "I will be that president."
This is the second national women's health group to back Clinton. NARAL Pro-Choice America PAC endorsed Clinton earlier this week, their president stating that Clinton "has what it takes to fight Republican attacks on women's reproductive rights, and has the vision and experience to ensure women and families thrive."
A Planned Parenthood clinic in Colorado was the site of a shooting that killed three people in 2015. The shooter -- Robert Lewis Dear -- said in court that he was "a warrior for the babies" and that he was "guilty."
Clinton condemned the attack
. "Today and every day, we #StandWithPP," she tweeted on the day of the shooting. She later said the country should be "supporting Planned Parenthood, not attacking it."