Oscars 2017: Celebrities react to 'Moonlight' winning best picture after mix-up

"La La Land" was first mistakenly announced as the winner.

— -- It was the biggest moment of the night.

Many took to social media to express their sentiments, including Steve Harvey, who famously crowned the wrong Miss Universe in 2015.

Here are some of the reactions to last night's big snafu at the 89th Academy Awards, held at the Dolby Theatre in Los Angeles: