American Idol alum Jennifer Hudson put in a surprise performance Sunday during MTV's Video Music Awards, joining Seattle-based duo Macklemore & Ryan Lewis during their live performance of the gay marriage anthem Same Love.

While it was known that feature vocalist Mary Lambert would be sharing the stage with Macklemore & Ryan Lewis, Hudson's part wasn't.

As Macklemore rapped, Hudson appeared from behind to sing the song's chorus performed on the single by Lambert: “And I can't change; even if I tried; even if I wanted to; my love she keeps me warm.”

Slowly Lambert made her way to the stage's forefront and took Hudson's hand.

“I'm not crying on Sundays,” they each belted out, a melodic hook Lambert earlier explained was a reference to her difficulty in reconciling being gay and Christian. (The video is embedded on this page.)

The video for Same Love also won the VMA for Best Video with a Social Message. (Watch the video in our video library.)

(Related: Macklemore says gay rights are human rights in accepting VMA award.)

Lambert earlier this week debuted the video to She Keeps Me Warm, which she described as “the other side of the Same Love story.” (Watch the video in our video library.)