Originally, the issue had been something of a three way between Google, Apple and wireless US phone carrier AT&T who, it was believed, wanted the app squashed so its customers wouldn't be able to make cheap international calls on AT&T's own network.
But with everything out in the open, the AT&T conspiracy theory has now dissolved, albeit leaving Apple a little bit red faced.
The reason for the rejection by Apple was apparently that the firm "believed the application duplicated the core dialer functionality of the iPhone" according to Google's letter.
Google's letter to the FCC also notes that Apple also rejected its Google Latitude app, claiming it to be potentially confusing for users who already had a built in Maps application which ships with the iPhone.
Apple has been trying to become a tad more open about its app store approval process of late, but the emergence of Google's correspondence with the FCC hasn't done the firm any favours.
Still, Google - whose CEO Eric Schmidt used to sit on the Apple board - is being magnanimous about the incident, noting "We continue to work with Apple and others to bring users the best mobile Google experience possible," he said.