Peter Bjorn & John are a pop trio from Sweden best known for their 2006 single "Young Folks," a tune that's easily recognizable by its whistling intro.

Affectionately dubbed PB & J, friends Peter Morén, Björn Yttling and John Eriksson formed the band in 1999, apparently with humble ambitions: to make music for their own amusement. Ten years and five albums later, the group has gained an international fan base including none other than Kanye West [ tickets ]. The rapper sampled "Young Folks" for his mixtape album "Alter Ego," and was so impressed with their new single, "Nothing to Worry About," he ended up leaking it on his blog.