Oscar host Jimmy Kimmel vowed to give U.S. President Donald Trump something to tweet the night after the show, by calling on the Academy audience to applaud the "highly overrated" Meryl Streep.

Kimmel, who referred to Trump throughout his opening monologue, wrapped it up by referring to Trump's recent tweet that Streep is "over-rated."

"One actress has stood the test of time for her many uninspiring and overrated performances," Kimmel told the audience on Sunday. "Meryl Streep has phoned it in for over 50 films over the course of her lacklustre career. This is Meryl's 20th Oscar nomination."

Kimmel urged Streep to stand while the audience applauded her. Then, just before she sat down, her commented on her dress. "Is that an Ivanka?"

The late-night talk show host urged Americans to mend the deep divides in the country by reaching out to their enemies. In an attempt to do just that, Kimmel reached out to nemesis Matt Damon in his monologue, praising him for surrendering a possible starring role in "Manchester By The Sea" to make "a Chinese ponytail movie ('The Great Wall') instead."

Kimmel pointed out that the film lost $80M, adding: "Smooth move dumbass. See? It's so easy to reach out and heal."

Kimmel often plays up a "feud" with Damon on his show, claiming on many occasions that he's run out of time to bring Damon on for an interview.

Also on Sunday night, Kimmel suggested Hollywood had finally put its #OscarsSoWhite controversy to bed with this year's films, because "black people saved NASA and white people saved Jazz. That's what you call progress."

He also hailed some of the lesser-known Academy Award nominees, saying: "Too often, the Academy only recognizes movies that people have seen."

Finally, at the end of the speech, Kimmel offered some tongue-in-cheek encouragement for those nominees who might be hoping to denounce Trump in their acceptance speeches.

"Some of you will get to come here on stage and give a speech that the president will tweet about in all caps during his 5 a.m. bowel movement tomorrow," he said.

Later in the show, Kimmel ushered several tourists through the theatre, introducing them to the celebrities seated in the front row. Denzel Washington "married" an engaged couple, Jennifer Anniston handed over her sunglasses to one woman, and Mahershala Ali allowed each of them to touch his Oscar trophy. Many of them also stopped to kiss Meryl Streep's hand.

Meanwhile, Kimmel took several shots at Damon throughout the show, including during a segment reviewing Damon's film, "We Bought a Zoo."

"The thing about Matt is you can see how hard he's working. It's so effortful for him," Kimmel says in the segment. "That's the thing about Matt. He has almost no discernable talent, but he works."

After the segment, Damon and his former "Good Will Hunting" writing partner Ben Affleck took the stage to present an award. They were announced as "Two-time Academy Award winner Ben Affleck and guest," and each time Damon spoke, the orchestra started playing him off.

"You can't play me off, I'm presenting," Damon said.

"Wrap it up, we want to go home!" Kimmel yelled.