British singer Dido won't be walking the red carpet at the 2011 Academy Awards. She's expecting a baby and cannot fly to the show in Los Angeles.

But the sacrifice will be worth it one day, according to "127 Hours" composer A. R. Rahman.

"Her son or her daughter will be able to say that their mom didn't go to the Oscars just for me," Rahman said, with a grin, in an interview with Canada AM from London, England.

The Indian film composer and "White Flag" singer joined forces on the "127 Hours" song, "If I Rise."

Rahman, 45, wrote the music. Dido, 39, penned the lyrics.

Now the tune and duo are included in this year's Oscar race for Best Original Song.

"It's such an emotional story," Dido told Canada AM.

Like many moviegoers, Dido was inspired by this gripping, real-life survival tale based on Aron Ralston's 2004 book, "Between a Rock and a Hard Place.

The film adaptation from director Danny Boyle recounts Ralston's fight for survival after a fall down a Utah cave in 2003.

A boulder trapped Ralston's arm, leaving the mountain climber trapped for five days. With no rescue in sight, Ralston amputated his arm with a dull knife to save his life.

"If I Rise" plays during the movie's big scene.

That life-or-death moment, played out by James Franco on screen, is jacked up even further thanks to the song's rousing chorus performed by The Gleehive Children's Choir from Mumbai.

"We both felt that using too many lyrics in the verse would be intrusive…So I just closed my eyes and thought about the story," said Dido.

The music video premiered on the Wall Street Journal website on February 17.

"If I Rise" faces strong competition

It featured Dido singing and Rahman playing the Harpejji, a combination guitar-keyboard instrument that is used heavily in the film's track.

Despite such original touches,  "If I Rise"  is up against tunes from "Country Strong," "Tangled," and "Toy Story 3" in this year's Best Original Song category.

Rahman and British indie singer Florence Welch (Florence and the Machine) should deliver one of the night's most unique moments when they perform "If I Rise" together on stage.

But that Oscar limelight is nothing new to Rahman.

The musician and record producer collaborated with Boyle on 2008's Oscar-winning film, "Slumdog Millionaire."

Rahman won two Academy Awards in 2009 for Best Original Music Score and Best Original Song.

Boyle hired Rahman once again to create the score for "127 Hours -- a film which has earned six Oscar nominations, including Best Picture and Best Actor for Franco.

Unlike Rahman, this year's Best Original Song nomination was a first for Dido.

"I was completely surprised," Dido told Canada AM.

The London-based singer-songwriter became a worldwide sensation with her 1999 debut Album, "No Angel," which sold more than 21 million copies worldwide.

Her 2003 album, "Life for Rent," also enjoyed huge success thanks to the hit singles, "White Flag" and "Life for Rent."

Even if her Oscar experience is enjoyed from afar this year, Did owes it all to a single phone call.

"I gave her a call and asked whether she'd be interested," Rahman said.

"She saw the script. She read the script. That was that."