The horror author is the latest public figure to share his opinion on the midterm elections, which will be held this week.
Stephen King has told his Twitter followers to vote out controversial Iowa Rep. Steve King, who is also the writer’s namesake.
He wrote: “Iowans, for personal reasons I hope you’ll vote Steve King out.
“I’m tired of being confused with this racist dumbbell.”
The Republican congressman has hit the headlines for the wrong reasons in the past over his support of groups holding white-supremacist views.
Last summer, he spoke to a publication which was linked to Austria’s Nazi-founded Freedom Party.
He also reportedly said diversity was “not a strength”.
Steve King was previously a clear winner in his campaign against Democrat JD Scholten.
But now many Republican leaders have condemned him, while a number of companies said they will no longer contribute to his campaign.
Some of Steve King’s old tweets and statements have gained further controversy following the Pittsburgh synagogue shooting last weekend.
A man was thrown out of an event in Iowa after he said Mr King and the gunman “both share an ideology that is fundamentally anti-immigration”, according to the Pittsburgh Post-Gazette.
Author Stephen King is known for being a critic of Mr Trump and his fellow Republicans.
Voters will take to the polls on Tuesday, November 6, to choose their favourite candidates for the US Congress, governorships and local elections.
At least 20 million people in America have already cast their ballots for the midterms.
But most polling stations will open at 7am, although times may vary.
Results are then expected to begin to trickle in during the early hours of November 7.