Drummer Alan White once claimed he played on "My Sweet Lord" with Carl Radle on bass and Starr on tambourine, and with John Lennon among the rhythm guitarists. Leng lists John Barham as the probable harmonium player; Beatles historian Bruce Spizer says that Peter Frampton may have added acoustic guitar after the main session. The chorus vocals were all sung by Harrison and credited to "the George O'Hara-Smith Singers". These contributions, together with Harrison's slide guitar parts and Barham's orchestral arrangement, were overdubbed during the next two months, partly at Trident Studios in central London. Harrison experimented with several harmony ideas in his guitar parts, having first applied himself to mastering slide during the 1969 Delaney & Bonnie tour.