The 1989 World Tour has been full of surprise guests and new songs. Taylor Swift sang "Never Grow Up" for the first time on tour during her performance Saturday night.

Swift wrote the song for her Speak Now album (2010). During the concert, she dedicated it to her baby godson, Leo Thames.

The pop singer delivered a short speech before performing the song.

Standing on top of the crowd with her guitar, she said, "I wrote it when I was 18 or 19, but my friend just had a baby, and she made me godmother of it.

I was holding this little baby the other night. I was just thinking differently."

The singer said that as she held the newborn, he seemed "so innocent and so perfect."

"The world is going to throw so many things at you as we grow up," she added right before singing.

Jaime King, Swift's friend and the mother of Swift's godson, thanked the star on Twitter. "This is so beautiful Tay. Leo Thames is so blessed," she tweeted.

Earlier this summer, Swift was pictured holding the newborn. She posted the photo on Instagram and captioned the post with lyrics from "Never Grow Up."

Check out the heartfelt introduction to "Never Grow Up" during the show in Santa Clara below. Swift is continuing her tour and heading to Arizona this weekend.

Photo courtesy of INFphoto.com