On May 1, 1970, Howlin' Wolf arrived in London to record with British players, especially guitarist Eric Clapton. He was accompanied by producer Norbert Dayron, Chess company chief Marshall Chess, Wolf's life-long guitarist Hubert Sumlin, and harp player Jeffrey M. Carp. In an interview Dayron recalled that he secured the co-operation of Clapton earlier in the year, but it is also safe to assume that the well-connected Glyn Johns, engineer at Olympic Sound Studios, was instrumental in gathering the musicians who eventually appeared on the sessions (May 2-7, 1970).
On the first studio day (May 2) a hurriedly put-together assembly consisting of Eric Clapton, Ian Stewart, bass player Klaus Voorman and Ringo Starr backed the Chicago contingent on three tracks, but Voorman and Starr in particular had trouble adjusting to Wolf's needs, and both of them decided not to return to the sessions. They were replaced by Bill Wyman and Charlie Watts. Wyman and Watts have a natural affinity for the music and, teamed with Stu's piano, probably no other British rhythm section could so well approach the true Chess sound as these three.
Adapted from the following source: Christopher Hjort, Strange Brew. Eric Clapton & The British Blues Boom, Jawbone, 2007.