I have been reading some of the above posts. Cher did sing on Da Doo Ron Ron as she has always stated the first record she sang on was the Ronettes' Be My Baby. Dee Dee Kenniebrew says that they did the backups in NYC after La La had gone to Calif. to record the lead.
Anyway, I did not like20 Feet documentary. Followed no chronological order. Where were the Cookies or the Andantes??? The Cookies sang on so many hits in NYC--Neil Sedaka, Bobby Vee, Eydie Gorme's "Blame It On The Bossa Nova", etc.

There was a group of older women in Phila. connected to the Clara Ward Singers who did backups for Cameo-Parkway artists like Bobby Rydell, Chubby Checker, DD Sharp.