Complex sentence: He was soon touring with the successful Swedish pop star, Björn Skifs' "Blue Swede" who got to number 1 in the U.S. pop charts with "Hooked on a feeling".
Split into simpler sentences: He was soon touring with the successful Swedish pop star, Björn Skifs. His band, Blue Swede, recorded a number one hit song in the U.S. pop charts with "Hooked on a Feeling".