The striker was only the second Italian to play for Los Blancos but he managed a miserly two goals and provided just three assists in 19 outings for the club in the league.
Cassano spent two years in Madrid; serving as part of the team that won La Liga in 2007 but his time in the Spanish capital was tumultuous and he spent his second season at the Santiago Bernabeu on loan at Sampdoria.
The Italian has now offered some fascinating insight into his stint in Spain which revealed how he ended up putting on excess weight and struggling to maintain his discipline off the pitch.
In quotes carried by Marca, the former footballer told Bobo TV: “When (boss, Fabio) Capello arrived I scored two goals in two games and I felt like the king of the world. He then replaced me in the first half against Lyon, I fought with him in Jerez and he took me out of the team.
“In seven months I gained 14 kilos, I ate Nutella straight from the pot, by the spoonful, and nothing mattered. It was disgusting.
“I am very sorry to Capello, a person I really love. ”
Cassano has played for Bari, Roma, Real Madrid, Sampdoria, AC Milan, Inter, Parma, Hellas Verona and the Italian national team during his colourful career.