Vice President Pence will address the March for Life in Washington on Friday, becoming the first vice president to do so, The Washington Post reports.

No president or vice president has spoken at the annual pro-life rally since its inception in 1974. Former President Reagan delivered a pre-recorded video message for the march in 1988, and former President George W. Bush made a phone call to rally-goers in 2008.

President Trump adviser Kellyanne Conway is also set to speak at the march, according to the Post.

{mosads}Pence has been a longtime opponent of abortion and, in his previous role as governor of Indiana, signed some of the nation’s toughest anti-abortion legislation.

Trump’s stance on abortion appears to have evolved over time. In 1999, he described himself as “very pro-choice.” But by 2011 he began to oppose the procedure, maintaining that position into his presidency.

Trump signed an executive order Monday reinstating a ban on providing funding to nongovernmental groups that discuss or perform abortions abroad.

In an interview with ABC anchor David Muir this week, Trump accused news outlets of not covering the March for Life, despite the massive size of the demonstration, which he said could exceed that of the women’s march protesting his inauguration last weekend.

“You’re going to have a lot of people coming on Friday,” he said. “And I will say this, and I didn’t realize this. But I was told you will have a very large crowd of people. I don’t know as large or larger. Some people said it will be larger, pro-life people, and they say the press doesn’t cover them.”