Find yourself a tissue box, because the story behind Taylor Swift's surprise Tonight Show performance is a serious tearjerker. Host Jimmy Fallon returned to the show Monday night (November 14) for the first episode since his mother, Gloria, passed away on November 4. In a heartfelt tribute, he shared one of their special moments with the audience.

"When we were little, my mom would walk us to this store, me and my sister, and we would hold hands," Fallon said through tears. "She would squeeze my hand three times and say, 'I love you,' and I would squeeze back, 'I love you too.' And last week I was in the hospital and I grabbed her hand and I squeezed, 'I love you,' and I just knew we were in trouble."

The episode continued as usual, with Swift stepping in as the night's unscheduled performer. Needless to say, the audience was stoked when she sat down next to a piano for "New Year's Day," Reputation's stripped-down final song.

The song's haunting second verse particularly resonated across Studio 6B: "You squeeze my hand three times in the back of the taxi / I can tell that it's gonna be a long road / I'll be there if you're the toast of the town, babe / Or if you strike out and you're crawling home."

In the happiest of coincidences, Tay's "New Year's Day" lyrics perfectly line up with Fallon's earlier anecdote. The audience, cast, and crew had zero clue ahead of time.

"I nearly gasped," writer and producer Mike DiCenzo tweeted after the show. "I could see Jimmy silhouetted at his desk dabbing his eyes with a tissue. We all lost it."

"I'm just realizing Taylor didn’t readjust the song's lyrics for tonight’s performance," Questlove added. "But the narrative literally applies to the words Jimmy spoke of his mother. Wow. You can't plan these things."

For more on Reputation, watch MTV News' visual essay on Swift below.