After a short breakup period, Robin Gibb reunited with Barry Gibb and Maurice Gibb to restore the central three-brother unit of the Bee Gees. They entered the 1970s with the successful Two Years On album and scored one of their biggest pre-disco era hits with "Lonely Days." The lyrics to "Lonely Days" seem to be typical pop-song fodder, consisting of musings about "Mister Sunshine" and a chorus that intones "Lonely days, lonely nights/Where would I be without my woman?" However, the hook-laden melody makes it easy to see why this song became an international chart-topper. "Lonely Days" combines the group's knack for strong hooks with an unusual and surprising song structure that combines elements of balladry and up-tempo pop: the verse melodies have a slow, somber ballad tempo that unexpectedly shift to a bright, major-key style for the sunny mid-tempo chorus. The Bee Gees' recording plays this unusual dichotomy up with a clever arrangement that utilizes ballad-style orchestration and piano on the verses then replaces those elements with a handclap-laden beat and swinging horns on the choruses. The resulting fusion of ballad sweetness and pop hooks topped the charts in the U.S. and allowed the Bee Gees to reestablish themselves as proponents of the singer/songwriter genre, a stylistic turn that would soon yield more hits like "How Can You Mend a Broken Heart" and "Run to Me."