Phoebe Bridgers makes a surprise appearance on NBC’s “The Tonight Show Starring Jimmy Fallon,” performing her song “Lost Boys.” Multiple outlets report the performance is connected to the track’s TV debut, giving viewers their first live broadcast of the “Lost Weekend” song. Bridgers is accompanied by a backing band made up of children and young teenagers. One report describes the group as consisting of viral rising musicians aged roughly 8 to 14, while another notes they serve as the backing band during the performance. The band members accompany Bridgers throughout the rendition, with the setup emphasizing the unusually young lineup rather than any change to the song itself. The outlets agree that the appearance is unannounced or presented as a surprise, and they publish video of the performance for viewers to watch. No additional changes to the track, production details, or comments from Bridgers are reported in the provided summaries.