Harris will perform the multimedia sequence 'Moving Pictures' while hosting the show on February 22.
"On the heels of the international success of last year's 'Frozen' and their Oscar for 'Let It Go' we couldn't be happier to have Kristen and Bobby Lopez write an incredibly special song for Neil Patrick Harris and special guests to perform this year on the Oscar stage," said show producers Craig Zadan and Neil Meron in a statement.
"We love the Oscars and have always been huge Neil Patrick Harris fans, so when he asked us to write him a song for this year's show we said, 'Yes!' before he could finish the sentence - it's possible he may have been asking us for something else," they said.