The 38-year-old recording artist, who snagged his biggest acting gig to date with La La Land, will perform two nominated songs from the musical, "City of Stars" and "Audition (The Fools Who Dream)," at the awards show.
"Practicing for La La with Luna," Legend wrote on Thursday, next to an adorable snap of one-year-old Luna sitting on his lap while he plays the piano.
Legend's Oscar, and 10 GRAMMY awards, are also featured in the background of the snapshot.
The Damien Chazelle-directed La La Land landed 14 Oscar nominations including Best Picture, Best Original Screenplay, and Best Leading Actor and Actress nods for stars Ryan Gosling and Emma Stone.
Meanwhile, this weekend’s Academy Awards mark Legend’s third consecutive live TV performance, after headlining the NBA All-Star Game halftime show last Sunday, and performing the "In Memoriam" tribute at the GRAMMYs a week earlier.