"Lose Yourself" helped Eminem win an Oscar in 2003 -- for best original song. But he didn't come to the ceremony to accept it.
After he took the stage Sunday, Eminem tweeted, "Look, if you had another shot, another opportunity... Thanks for having me @TheAcademy. Sorry it took me 18 years to get here."
Laura Dern’s first Oscar
Best supporting actress winner Laura Dern gave a sweet, heartfelt speech when she won her first Oscar for her role as a headstrong divorce lawyer in "Marriage Story."
Among her thank-yous were her parents, actors Diane Ladd and Bruce Dern.
"Some say, never meet your heroes, but I say if you're really blessed, you get them as your parents. I share this with my acting heroes: my legends Diane Ladd and Bruce Dern," she said as the audience erupted in cheers. "You got game. I love you."
In 2014, Pitt won a best picture Oscar for producing "12 Years a Slave."
The A-lister briefly got political in his acceptance speech, saying his 45 seconds to speak on stage is 45 more than "the Senate gave [former national security adviser] John Bolton this week" during the impeachment trial.
To his costar, Leonardo DiCaprio, Pitt said, "Leo, I'll ride on your coattails any day, man. The view is fantastic."
Pitt ended his speech with a shoutout to his six children with ex-wife Angelina Jolie.
"This is for my kids who color everything I do," he said. "I adore you."
Steve Martin and Chris Rock crack diversity jokes
Comedians Steve Martin and Chris Rock, who introduced the show, addressed this year's lack of female directors and actor diversity.
"Cynthia Erivo is here tonight," Rock said. "Cynthia did such a great job in 'Harriet' hiding black people that the Academy got her to hide all the black nominees."
Cynthia Erivo, who was recognized in the best actress category for her role as Harriet Tubman in "Harriet," is the only person of color to be nominated in the acting categories, along with 19 white actors and actresses.
Martin told the crowd, "Think how much the Oscars have changed in the past 92 years... back in 1929, there were no black acting nominees."
Then Rock added: "And now in 2020, we got one."
Janelle Monáe's musical number
Janelle Monáe opened the show with a musical number featuring Billy Porter, and even got celebrities -- including Leonardo DiCaprio -- singing along.
Monáe gave a shoutout to the women who directed films this year -- a jab at the Academy, after no women were among this year's best director nominees.
"Tonight, we celebrate all the amazing talent in this room," she said. "We celebrate all the women who directed phenomenal films and I'm so proud to stand here as a black, queer artist, telling stories. Happy Black History Month."
ABC News' Jesse Convertino contributed to this report.