Monday marked the first day back to work for "Tonight Show" host Jimmy Fallon after the sudden passing of his mother, Gloria, earlier this month. Fallon opened the show with a tearful tribute to his beloved mom, featuring an anecdote that would coincidentally come back into play during an emotional performance from Taylor Swift.

After his monologue, the comedian thanked fans for their support during such a difficult time for his family, and said that his mother was "the best audience."

"She was the one I was always trying to make laugh, and she was such a fan of the show, and everything I did," Fallon said, fighting back tears. " ... Mom, I'll never stop trying to make you laugh. I love you."

The host also told a story about his childhood, when his mom would squeeze his hand three times as she said, "I love you," and he would squeeze her hand back and say, "I love you, too." Fallon said he knew that Gloria's health was taking a turn for the worse when he squeezed her hand in the hospital, and she did not respond in kind.

In what would turn out to be an incredible coincidence, Swift was called in as a last-minute musical guest for the show, and debuted a new song from her album "Reputation," called "New Year's Day." The track contains the lyric, "You squeeze my hand three times in the back of the taxi," an unintentional surprise callback to the story Fallon had told earlier.

It was a connection that the "Tonight Show" crew didn't even realize existed, as explained by writer and producer Mike DiCenzo on Twitter.

And DiCenzo added that there was one additional surprise, especially for Gloria, added into the end of the show.

What a beautiful story, and what a beautiful tribute to Gloria. It's getting misty in here...

[h/t BuzzFeed]