"I'm so honored to have a small part in your giant musical legacy," Bruno Mars told Lady Gaga upon accepting the award for best pop duo/group performance

In a stirring tribute to a city in crisis, Lady Gaga and Bruno Mars sang "California Dreamin'" at Sunday night's Grammys ceremony.

Of course, this isn't the first time Lady Gaga and Bruno Mars have collaborated. Their surprise duet "Die With a Smile" continues to be one of the biggest radio and streaming hits out today since it's initial release last year.