Oscars 2020 live updates: Eminem's unexpected performance, Brad Pitt's big win

The Oscars ceremony -- Hollywood's biggest night of the year -- is finally underway, with celebrities from Leonardo DiCaprio to Scarlett Johansson up for the big awards.

Here is how the award show is unfolding. Please refresh for updates.

Eminem makes a surprising appearance 

Rapper Eminem made an unexpected appearance on stage, performing his hit "Lose Yourself" from the 2002 movie "8 Mile."

By the end of his performance, everyone in the star-studded audience was on their feet.
 

When @Eminem starts performing... ? #Oscars pic.twitter.com/aY9DYbmqTf

— ABC (@ABCNetwork) February 10, 2020

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."

Laura Dern's mom came with her as an Oscars date.

Brad Pitt's first acting win

Brad Pitt won his first Oscar for acting, picking up the best supporting actor Academy Award for his work in Quentin Tarantino's film, "Once Upon a Time... in Hollywood."

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.