Common and John Legend win Oscar 2015

Musicians Common and John Legend accepting the Oscar for Best Original Song for "Glory" from "Selma" on stage  at the 87th Oscars February 22, 2015 in Hollywood, California. 

ROBYN BECK/AFP/Getty Images

Politically and historically aware speeches from Common and John Legend received the biggest ovation of the first two and half hours of the Academy Awards on Sunday night.

Oscars 2015

The rapper and singer, honored with the best original song Oscar for "Glory" from Selma, connected the dots between the marches of Dr. Martin Luther King Jr. 50 years ago and events in the world today that affect civil rights, freedom of speech and voting rights.

"Recently John and I got to perform 'Glory' on the same bridge Dr. King marched on 50 years ago," Common said in his acceptance speech. "The spirit of this bridge transcends race, religion, sexual orientation, social status and connects a kid from the south side of Chicago to France to Hong Kong."

2015 Oscars: See All the Photos

Legend quoted Nina Simone, saying it's an "artist's duty to reflect the times in which they live. We say Selma is now." He pointed out issues such as voting rights and the number of imprisoned African-Americans. "The struggle for freedom and justice is real," he said.

"Glory" had been considered the front-runner in the category and the song received significant exposure when Common and Legend performed it earlier this month on the Grammys when Oscar ballots were in the hands of voters. The Oscar producers seemingly sensed its likelihood of a win, saving it for the last performance of the nominees and allowing the performance to last longer than the others.

In the other music category, composer Alexandre Desplat won his first Oscar after eight nominations, taking home the original score trophy for The Grand Budapest Hotel. Desplat was also nominated this year for his work on The Imitation Game.

He dedicated his award to his wife, a violinist he met at a scoring session decades ago. "You made everything happen for me," Desplat said.