http://soulfuldetroit.com/showthread...pson-Interview

Q. There are some Motown people who contend that near the end of Tammi Terrell's life (she died in 1970 at age 24 of cancer), you had to step in and do some of her vocal parts on the albums with Marvin Gaye because she was too ill to perform. Is that true?

A. Tammi was very ill. We would have everything ready, the track and Marvin's vocal, and then I'd get her alone in the studio and we'd go line by line. There were a couple things that were tweaked, but not a lot. I couldn't just sing like Tammi. People give me the credit of thinking I could be Tammi Terrell, but it's just not true. We did some production edits to fix things, but that's about it.

"There were a couple things that were tweaked, but not a lot. We did some production edits to fix things, but that's about it."
" I'd get her alone in the studio and we'd go line by line."

I take that as she is saying in fact it was both of them. At some points Val was "punched in" , she may have emulated Tammis diction as close as possible and then they may have EQ' d and proccessed for tone.

"I couldn't just sing like Tammi. People give me the credit of thinking I could be Tammi Terrell, but it's just not true."

Words of admiration from one artist regarding anothers gift. Delivered with class and grace.
If the truth is the light ,as the saying goes, then Ms Valerie has indeed just flicked the light switch on.