Taylor Swift made an unscheduled appearance on “The Tonight Show” on Monday night to perform a song from her new album and helped honor Jimmy Fallon’s mother who passed away last week.

“As some of you know, my mother, Gloria, passed away recently,” a very emotional Fallon said at the top of his broadcast on Monday. “She was the best audience. She was the one I was always trying to make laugh. She was such a fan of the show, and everything I did.”

During a tribute to his mother, Fallon told a story about how his mom would hold his hand as a kid, and would squeeze his hand three times and tell him that she loved him.

“When we were little, my mom would walk us to the store, and we would hold hands. And she would squeeze my hand three times and say ‘I love you.’ Last week I was in the hospital, and I grabbed her hand and squeezed ‘I love you.’ I just knew we were in trouble.”

Near the end of the show, Swift performed “New Year’s Day.” The lyrics include a line about squeezing a loved one’s hand three times:

“You squeeze my hand three times in the back of the taxi, I can tell that it’s gonna be a long road”

Mike DiCenzo, a writer for the show, shared the story behind Taylor’s emotional performance in a series of tweets:

“Jimmy’s words about his mom were beautiful. “Mom, I’ll never stop trying to make you laugh. I love you.” I was crying. We all were. The story about his mom squeezing his hand 3 times to say “I love you” when he was a kid, and then him squeezing her hand in the hospital – he hadn’t told any of us that story…

First, a quick word about Taylor Swift. She was not scheduled to do our show today. But we wanted something special for this first show back, so we asked her on a complete whim, since she had been in town doing SNL. She said yes with zero hesitation.

She sang “New Year’s Day.” No one had heard it. Suddenly she sings the line, “Squeeze my hand 3 times in the back of the taxi.” I nearly gasped. Tears. I think everyone in the audience started sobbing. I could see Jimmy silhouetted at his desk dabbing his eyes with a tissue. We all lost it. It was a beautiful coincidence in a beautiful performance.

“Hold on to your memories, they will hold on to you,” Taylor sang. That hug between Jimmy and Taylor after the song was 100% real emotion. Whatever you think of Taylor, she did something beautiful for Jimmy and our show today, and we’re forever grateful.

Thank you to Taylor, the Roots, Higgins, our whole staff and crew, and to all the FalPals, fans, and everyone who reached out to and supported Jimmy and his family. I can tell you it meant everything to him