Donald Trump will this evening address thousands of social conservative grass-roots voters at the influential Values Voter Summit in Washington DC.
Vice presidential candidate Mike Pence, governor of Indiana, will address the summit, the 11th annual event of its kind.
Tomy Perkins, president of the organisers, Family Research Council Action, said in a press release: "As the 2016 presidential election approaches, there is a growing realisation among voters that the future of our freedoms and even our identity as Americans hangs in the balance.
"I am certain that Donald Trump and Mike Pence will underscore not only the importance of this election, but the important role conservative Christian voters have in influencing the outcome of the November election."
This will be the first time a GOP presidential ticket has attended since the three-day event began in 2006.
Perkins said it shows "an understanding of the importance of values voters in the general election and a desire to work with them in addressing the critical issues facing our nation."
Actors Jon Voight and Kirk Cameron are also due to speak as well as Michele Bachmann and Rick Santorum.
"Those candidates coming to the summit are showing that they value social conservative voters and want to have a conversation with them. We will encourage attendees to take the candidates' presence into account as they cast their vote in the straw poll," added Perkins.
Trump's address will be live-streamed from the summit.
Barry Lynn, executive director of Americans United for Separation of Church and State, told the Washington Times that Trump is an odd standard-bearer for the issues social conservatives care about.
