President Trump: "Every child born and unborn is made in the holy image of God."
Trump will be the first president in U.S. history to attend and speak at the annual March for Life.
President of the march Jeanne Mancini said: "We are deeply honored to welcome President Trump to the 47th annual March for Life."
Mancini explained why she's marching: "Abortion is the human rights abuse of today and we've lost 61 million Americans to abortion."
Trump simply tweeted: "See you on Friday ... big crowd!"
President Trump also declared Jan. 22 the "National Sanctity of Human Life Day."
He called on Congress to join him "in protecting and defending the dignity of every human life, including those not yet born." And he called on the American people "to support adoption and foster care in a more meaningful way, so every child can have a loving home."
The president's declaration comes on the anniversary of the Supreme Court's 1973 decision in Roe v. Wade.
Fr. Frank Pavone of Priests for Life has called the ruling "The most destructive decision in the history not only of the court but of human history."
Pro-life advocates are hoping that Trump's one-two punch is the knockout blow that foreshadows an end to legal abortion in the United States.