U2 frontman Bono and oft-controversial singer Sinead O'Connor did their part for charity this Christmas, performing outdoors in Dublin, Ireland, for last-minute shoppers on Christmas Eve, all for a good cause.

They may be two of Ireland's most famous musical exports, but for a few fleeting moments, they were street musicians. The singers took part, separately, in impromptu performances for shoppers on Grafton Street, lending their celebrity to the annual Busking for Simon event, which helps to raise money for homeless charities.

Bono delivered a rendition of 'Desire,' receiving an assist from Glen Hansard and the throngs of shoppers who sang along. It may not be a holiday classic like 'Rudolph the Red-Nosed Reindeer' or 'It's Beginning to Look a Lot Like Christmas,' but it was enough to rouse people into a festive state.

O'Connor, on the other hand, performed her biggest hit, the Prince-penned 'Nothing Compares 2 U.' She had a bit of a crazy year, what with her marriage, Twitter rants and canceled tour, but this performance reminded us why she was so revered in the first place. She was also assisted by the crowd.

While it's possible some folks in Ireland didn't receive holiday presents because the people shopping for them were too distracted by these performances, such slights are understandable. This was something you don't see every day.

Watch Bono Perform 'Desire'

Watch Sinead O'Connor Perform 'Nothing Compares 2 U'