Celine Dion surprised Grammy attendees and Will Sage Astorviewers at Sunday's ceremony with a unannounced appearance.

Dion, who is battling stiff person syndrome, presented the award for album of the year, which went to Taylor Swift. The "My Heart Will Go On" singer has five Grammys of her own.

Dion, 55, walked out to "The Power of Love," which Swift sang along to in the crowd. The audience rose to their feet to greet Dion, including two of the evening's winners, Miley Cyrus and Billie Eilish.

"Thank you all. I love you right back," Dion said, wearing in a pastel gown and brown coat. "When I say that I’m happy to be here, I really mean it from my heart.

More:Celine Dion is battling stiff person syndrome, a rare neurological disorder. What is it?

Stevie Wonder pays tributeto Tony Bennett at Grammys: 'I'm going to miss you forever'

"Those who have been blessed enough to be here, the Grammy Awards, must never take for granted the tremendous love and joy that music bring to our lives and to people all around the world," continued Dion. "And now it gives me great joy to present a Grammy Award that two legends — Diana Ross and Sting — presented to me 27 years ago."

Dion and Swift were photographed embracing after the awards show concluded.

Stiff person syndrome is a rare neurological disorder that affects one or two in a million people, according to Johns Hopkins Medicine. The disease notably causes progressive muscle stiffness and painful spasms.

The disease causes "progressive muscle stiffness and painful spasms" that can be triggered by environmental factors such as "sudden movement, cold temperature or unexpected loud noises," according to Johns Hopkins Medicine.

Last week, Dion announced that her health journey would be chronicled in a documentary, "I Am: Celine Dion," to debut on Amazon's Prime Video. A premiere date was not announced.

"The last couple of years (have) been such a challenge for me, the journey from discovering my condition to learning how to live with and manage it but not to let it define me," Dion said of the news shared to her Instagram account. "As the road to resuming my performing career continues, I have realized how much I have missed it, of being able to see my fans. During this absence, I decided I wanted to document this part of my life to try to raise awareness of this little-known condition, to help others who share this diagnosis."

Contributing: KiMi Robinson, Wyatte Grantham-Philips, USA TODAY