The Marvelows Biography (Wikipedia)
The Marvelows were an American soul group from Chicago, formed in 1959. After contacting arranger / producer Johnny Pate, the group signed to the ABC-Paramount label, and recorded four sides: "A Friend", "My Heart", "Hey Hey Baby", and "I Do". Originally composed as a show warmup song, "I Do" was released as a single in the summer of 1965, and peaked at #7 on the R&B Singles chart and at #37 on Billboard's Hot 100. It was later covered twice by The J. Geils Band, first in 1977, and again on a live album in 1982.
The group changed its name to The Mighty Marvelows in order to avoid being confused with The Marvellos (Loma Records), after the Marvellos filed suit in 1964, and hit the charts only once more, with 1968's "In the Morning" (U.S. R&B #24). An LP followed, entitled The Mighty Marvelows, but the group broke up in 1969, reuniting only once, briefly, in 1974.