This Girl Sang 'Fight Song' While She Battled Cancer. Now, Ellen's Surprising Her With The Duet Of A Lifetime.

Beautiful.

When Calysta Bevier was just 15 she was diagnosed with ovarian cancer.

But in a heart-stopping, beautiful performance of Rachel Platten's "Fight Song," Bevier showed off just how strong she's been, fighting through chemotherapy and making it to remission. 

Video footage of her performance drew over 60,000 views on YouTube and it's easy to see why.

Then, Ellen DeGeneres caught wind of the performance and invited Bevier onto her show to perform for the audience.

But of course, DeGeneres had a major surprise in store for the well-deserving teen.

Rather than have her perform alone, DeGeneres invited Platten herself to sing a duet with Bevier.

The raw, emotional performance had audience members (and us) in tears. 

We can tell this is a performance neither singer will ever forget.

Sure sure to watch the full video below: