Singer's name?

k hes a finnish singer (from finland) but he sings english...hes blond and blue eyed and whatever...he did a song with this other blond america singer...i dont remember the songs name but in the middle it has i can't lett go....and he did another song with another singer that has curly hair and playes the gittar...and there like walking backwords the whole time....who is he plzz i love his songs?