NEW YORK — The race for the best original song Oscar is a slim one with two songs up for the honour, a first for the Academy Awards.

Sergio Mendes' "Real In Rio" from the animated adventure "Rio" will compete with Bret McKenzie's "Man or Muppet" from "The Muppets," despite having songs from a bevy of all-star musicians like Elton John, Mary J. Blige, will.i.am and Pink in contention for nomination.

Charles Bernstein, the former chairman of the Academy Awards' music branch, says he "personally was surprised" that only two songs are up for the honour.

In the past, the number of nominees for best original song has ranged from three to 14. Only up to five songs are eligible for nomination.

"I personally felt that there may have been more than two that I personally would have championed," he said in an interview after the Oscars nominations were announced Tuesday. "But it is a majority vote situation."

Blige, who co-wrote a song for the Deep South drama "The Help," said in a tweet Tuesday that she was sad, and felt like the Academy "is being mean" for only nominating two songs for the award.

This year, 39 songs were eligible for nomination for best original song, including tracks from Brad Paisley, Robbie Williams, The National, Zooey Deschanel, Zac Brown, Chris Cornell and others.

Members of the music branch can rank songs using 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5 or 6, and a song must have at least an average score of 8.25 to be nominated. If only one song gets that score, it and the song receiving the next highest score will be the two nominees.

Since two songs were nominated, it could mean that voters were unimpressed with this year's contenders.

"Each person is voting on a subjective impression ... so you'd have to go into the head of each individual voter to kind of know what it was that made them feel that any given song was or wasn't award-worthy," Bernstein said.

Bernstein also stressed that the songs "have to be written for the picture, and the judgment of its quality has a great deal to do with how it functions in the movie as well as how well written it is."

Bernstein, who did vote in the category, wouldn't say how many people voted this year, but did say that the rules for each Academy Award are carefully observed each year. He says the music branch will most likely take a closer look at the requirements for best original song after this year's results.

"It's very likely because there were two this year that the rules committee will probably take another look at it next year and make sure it wants to continue the same rules," he said.

Madonna's "Masterpiece," which won the Golden Globe for best original song and is from her directorial effort "W.E.," was not eligible for an Academy Award because "the song does not occur either in the body of the film, or as the first song at the end of the film," Bernstein said.

Mendes, who shares his nomination with Siedah Garrett and Carlinhos Brown, says "Rio" director Carlos Saldanha delivered the good news to him.

"I don't know much about the voting process really. I'm not an expert in that, but I'm so happy about me being nominated," Mendes said Tuesday afternoon. "I don't really know the criteria, but I can only think about celebrating."

Winners of the 84th annual Academy Awards will be announced Feb. 26 in a ceremony that will air live on ABC from the Kodak Theatre in Hollywood.