Humperdinck's version of "Release Me," done in a smooth ballad style with a full chorus joining him on the third chorus, reached the top ten on both sides of the Atlantic and went to number one in Britain, keeping The Beatles' adventurous "Strawberry Fields" from entering the top slot in the UK. "Release Me" also went on to become the longest running chart single in history. It spent 56 weeks in the Top 50 in a single chart run, a record that still holds to this day.
Even in a year dominated by psychedelic rock music, "Release Me"'s success may not have been that surprising, considering Frank Sinatra's chart comeback that began a year earlier, and stablemate Tom Jones's success with a ballad or two in the interim, both of which probably opened some new room for more traditionally-styled singers. "Release Me" was believed to sell 85,000 copies a day at the height of its popularity, and the song became the singer's signature song for many years.
And here is a charming clip of "Hump" and Dean Martin singing "Crosby, Sinatra, and Me":