"I Heard It Through the Grapevine" is a song written by Norman Whitfield and Barrett Strong for Motown Records in 1966. The first recording of the song to be released was produced by Whitfield for Gladys Knight & the Pips and released as a single in September 1967; it went to number two in the Billboard chart.

Answer this question based on the passage: who is the original singer of i heard it through the grapevine? OK. Let's think. My stream of consciousness:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
The relevant information is: The first recording of the song to be released was produced by Whitfield for Gladys Knight & the Pips and released as a single in September 1967; it went to number two in the Billboard chart. The answer is Gladys Knight & the Pips.