I was already at G.O.A.T. when I got this;
For 3 fights I went full length training camps and spent as much energy as I could in ‘Promote’ on Fight Hype.
When I was at training camp for my 4th fight the achievement popped while selecting Fight Hype and Popularity in ‘Promote’
When I got this achievement I had around 8.000.000 fans. The first 2 fights got to Very High Hype, but the third only to High Hype for some reason.