The pair fell out when Williams pulled out of a planned collaboration to record a track with hip-hop star Dizzee Rascal instead, and the former Take That member left a rude message on Professor Green's voicemail.
The rapper has written a song about the spat, and has decided to include Williams' message.
In the voicemail, Williams says, "Green it's Robbie Williams. I've just heard your album. Listen. A, keep my name out of your mouth. B, why do you have to go and mention (my flop album) Rudebox. It was a pretty s**ty time of my life. And C... it's f**k you, Green."
The stars have since made up and Williams agreed for the voicemail to feature in the track.
Green tells Britain's The Sun newspaper, "Me and him had a bit of a falling out... But then he reached out no long ago and said sorry for not sticking to his word. I'm cool with that, it takes a man to apologise... I told him I ended up taking a little jibe at him in the song and he suggested he had one back. So he did."
The message features in the track I Need Church.