A cool video has emerged of a U2 fan being invited on stage to play with the band. The footage, captured by an audience member at a concert at the Boston Garden, MT, US on Tuesday, shows the woman providing rhythm guitar accompaniment for hit song 'All I want is You'. According to the filmer, frontman Bono had earlier described his chance encounter with the fan - who is herself a musician - outside the venue. "Bono invited Gretchen Shae, guitarist/vocalist of local garage punk band The Knock Ups up on stage to play guitar on U2's 1988 hit 'All I Want Is You'. He mentioned that he had spoken to her on the street on the way into the venue and she had asked if she could play. Later on when he spotted her, Bono made Gretechen’s wildest dream come true."