The adorable couple went to Swift's show on Saturday night at Gillette Stadium in Foxborough, Massachusetts. As soon as the intro for "Gorgeous" came on, Lively grabbed her phone and started filming ... and then they both LOST THEIR MINDS when their daughter James' voice played for the whole crowd.
As the story goes, the young Reynolds ended up on the song after Swift was hanging out with Blake and Ryan and she began playing "Gorgeous" for them on the guitar. James kept saying "gorgeous" over and over and Taylor asked if she could use it.
The "Reputation" album booklet gives the 3-year-old the credit, saying, "Baby intro voice by James Reynolds."