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(Yahoo!) - A 4-year-old cancer patient received VIP attention when Sara Bareilles invited him up on stage for a duet while playing at House of Blues Orlando on her U.S. tour.

Joshua Chamber, who was diagnosed with leukemia last February and is now in remission, has a Facebook page entitled "Joshua's Journey - Be Brave" inspired by Sara's tune, so imagine his surprise when she let him jump in on his self-proclaimed theme song!

"Josh is one of the bravest little angels I've ever met, and he asked if he could come on stage and sing with all of you!" she told the crowd.

Not only did little Joshua sing, he did so like a pro. His delivery of the line "I want to see you be brave" was possibly the cutest rendition ever.

While Katy Perry's "Roar" has also become a battle cry for young cancer patients, the lyrics in "Brave" seem to fit perfectly for Joshua and it's no wonder it's his theme song.

To learn more about Joshua's journey, check out his site,, or visit his Facebook page or Twitter feed.

Check out the video to see this uplifting moment: