John Legend performs Nina Simone tribute at Sundance

The opening-night documentary at the Sundance Film Festival closed with a superstar concert.

After the credits rolled on "What Happened, Miss Simone?" John Legend took the stage to pay tribute to its subject, Nina Simone.

"I'm so grateful to be here today honoring the legacy of the wonderful, powerful, dynamic, super-talented Nina Simone," said Legend, who along with Common is nominated for an Oscar for their original song from "Selma."

The documentary about the late singer tracks her rise to fame, her struggles with mental illness, her activism during the civil rights movement, her move to Liberia where she left music behind and finally to France, where she regained her career.

Legend said the entertainer, who died in 2003, is "one of my favorite singers; one of my favorite artists of all time."

"I find myself studying her versions of all kinds of songs, thinking about her words, thinking about her boldness, thinking about her commitment to justice," he said. "I'm truly humbled to be here tonight to honor her legacy."

He emerged onstage from behind a screen seated at a grand piano, opening with Simone's soulful version of "Lilac Wine." He followed with "I Wish I Knew How It Would Feel to Be Free," which Simone made famous in 1967. After saying how much he admired Simone, he performed her 1964 single, "Don't Let Me Be Misunderstood."

Legend took a bow, then was embraced by the film's director, Liz Garbus, and festival founder Robert Redford.

Check out the performance below: