Carrie Underwood's official tour schedule may be slowing down as the pregnant country artist gets ready for the holidays, but on Monday she jumped in last minute for the World AIDS Day Event In New York City.

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According to Taste Of Country on Monday, the Something In The Water singer was asked by Bono himself to fill in for the U2 performance after the famous frontman was injured in a biking accident.

"The world reached a tipping point in the fight against AIDS," declared Bono in a press release regarding the event. "A lot of people are calling it the beginning of the end of AIDS… Americans don't know the role they've played in this fight. Tonight's event is to inform them and thank them."

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This is Underwood's second New York City event for a good cause this year. In September she headlined for the Global Citizen Festival, which had been organized in the fight against poverty.

Underwood's official tour schedule has her appearing on ABC and Fox this month, with one Nashville performance on Dec. 13. After that, the singer is not set to perform live until July.

In September Underwood announced that she and husband Mike Fisher, who plays in the NHL for the Nashville Predators, are expecting their first child together. Underwood is expected to give birth to their baby boy in the spring.

The singer's new album, Greatest Hits: Decade #1, hits stores on Dec. 9.

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