Robert De Niro said a Donald Trump victory in the US presidential election would be a "tragedy", as the actor was honoured at the Hollywood Film Awards.
The Oscar-winning star urged Americans to vote for Hillary Clinton as he compared Trump to the "totally insane" General Jack D Ripper from Stanley Kubrick's Dr Strangelove.
He said on stage: "It's two days until a frightening election. The shadow of politics is hanging over us whether we like it or not.
"It's hard for me to think about anything else so let me lay it out right here. We have the opportunity to prevent a comedy from turning into a tragedy. Vote for Hillary Tuesday."
The Raging Bull actor, 73, has previously voiced opposition to Trump, saying he wanted to punch the Republican candidate in the face in a video campaign last month.
Robert picked up the Hollywood Comedy Award for his portrayal of an ageing comic in the film The Comedian.
A host of A-list names were recognised at the ceremony in Beverly Hills - billed as one of the first award shows of the season - including Tom Hanks, Mel Gibson, Nicole Kidman and Leonardo DiCaprio.
Hugh Grant received the Hollywood Supporting Actor Award for his role in Florence Foster Jenkins, in which he starred opposite Meryl Streep.
The 56-year-old British star was presented with his award by Andie MacDowell, his co-star in the 1994 film Four Weddings And A Funeral.
Addressing Andie on stage, Hugh said: "I'm just depressed at how much better preserved you are than I am after 22 years. Do you use any special creams or anything like that?
"It's amazing. You're still a southern peach and I am, according to Twitter, a scrotum.
"I almost never get a prize and I'm so pleased with this one. It will not be in my loo or used as a doorstep."
Leonardo said it was "completely unacceptable" that climate change was not discussed in the election debates as he accepted the Hollywood Documentary Award for his environmental film Before The Flood.
"Let's all use our power as citizens and do the right thing" he said. "Please vote ... vote for people who believe in the science of climate change."
Eddie Murphy received the Hollywood Career Achievement Award in recognition of his film career, which has included starring roles in Beverly Hills Cop, 48 Hours and more recently as the voice of Donkey in the Shrek movies.
Natalie Portman picked up the Hollywood Actress Award for her portrayal of former first lady Jackie Kennedy in the film Jackie.
Nicole won the Hollywood Supporting Actress Award for her role as an adoptive mother in Lion, while Gibson received the Hollywood Director Award for his Second World War drama Hacksaw Ridge.
Tom collected the Hollywood Actor Award for his performance in Sully, in which he plays Captain Chesley Sullenberger, the pilot who safely landed a passenger plane on New York's Hudson River.
British actress and James Bond star Naomie Harris received the Hollywood Breakout Actress Award, while fashion designer turned film-maker Tom Ford won the Hollywood Breakthrough Director Award.
Actress Lily Collins, the daughter of musician Phil Collins, won the New Hollywood Award after starring in Warren Beatty's film Rules Don't Apply.
Justin Timberlake won the Hollywood Song Award for Can't Stop The Feeling from the animation Trolls. James Corden hosted the 20th annual Hollywood Film Awards at the Beverly Hilton Hotel.