The defender joined Liverpool this summer.
The 18-year-old was snapped up by former Liverpool boss Brendan Rodgers for a fee reported by the BBC to be in the region of £3.5 million.
Now his former chief executive has admitted Charlton had to sell the teenager. Katrien Meire told the South London Press this week that they could not stand in the way of Gomez once Liverpool had made their move.
"I promised Joe he could go when the right club came in. As much as I want to keep the players - and I will really try - sometimes it does not work to stop them. You cannot frustrate a player too long."
Gomez impressed early on at Anfield. He played seven games under Rodgers and impressed in his versatility across the back four, even if he did make the odd mistake that could be put down to age.
Unfortunately the teenager has not yet got the chance to play under Jurgen Klopp. He suffered a serious knee injury last month on international duty with the England under-21s and looks set to miss the majority of the season with the problem.