The Proclaimers are a Scottish band composed of identical twins Charlie and Craig Reid . They are best known for the songs "Letter from America", "I'm on My Way", and "I'm Gonna Be ". "I'm Gonna Be" became the theme song for the film Benny & Joon , and for several charity events, such as the Terry Fox Run and Red Nose Day 2007, as well as a Molson Canadian beer commercial. Inexplicably, they have a cult following in Australia.