Donald TrumpDonald TrumpUkraine's president compares UN to 'a retired superhero' Collins to endorse LePage in Maine governor comeback bid Heller won't say if Biden won election MORE is holding a sold-out campaign rally in Marshalltown, Iowa, where he is expected to be endorsed by outspoken immigration opponent Sheriff Joe Arpaio.

"I have fought on the front lines to prevent illegal immigration and I know Donald Trump will stand with me, and countless Americans, to secure our border," the Arizona lawman said in a statement released by the Trump campaign Tuesday afternoon. "I am proud to support him as the best candidate for President of the United States of America."

The event is slated to take place at the "Roundhouse" gymnasium at 7 p.m. EST.