The Righteous Brothers 

Like The Walker Brothers, The Righteous Brothers were not brothers at all. Bill Medley and Bobby Hatfield were a club act popular in southern California, but they attracted national attention in 1965 when Phil Spector provided them with the soulful classic You've Lost That Lovin' Feelin' - his and their finest hour, according to many. It became an instant worldwide number one, but by the end of the year their relationship with Spector had clouded, and they left his label.

(You're My) Soul and Inspiration reinstated them at the top of the charts, but from then on, it was downhill all the way, leading to their parting in 1968. 

Solo success was not forthcoming however, and six years later they reunited for a Top 10 return, Rock & Roll Heaven.