David Ruffin

Davis Eli "David" Ruffin (January 18, 1941 – June 1, 1991) was an American soul singer and musician most famous for his work as one of the lead singers of the Temptations from 1964 to 1968 (or the group's "Classic Five" period as it was later known). He was the lead voice on such famous songs as "My Girl" and "Ain't Too Proud to Beg."

source: Wikipedia