Shawn Mendes faced a travel nightmare en route to his London concert at the O2 Arena on Saturday night (August 16, 2025). The 27-year-old pop star was delayed after getting stuck on a broken-down train, leaving him with just minutes to rehearse with surprise guest Niall Horan before taking the stage. Introducing Niall to the audience for a performance of "This Town," Shawn explained, "I was on a broken-down train a couple of hours ago and barely made it, so we had about three to six minutes to practice this next song. Be easy on us." Despite the rushed preparation, the duo delivered a memorable performance.