Former Chelsea full-back has been discussing the professional dislike between two stars of Barcelona's 2006 Champions League winning side.
Samuel Eto'o, who like Belletti scored in the Paris final against the Gunners, was not a fan of former Ballon d'Or winner Ronaldinho and vice versa.
Belletti was speaking to Brazilian television, contrasting the pair to Lionel Messi and Neymar, the two present day stars of Barcelona.
He said: "I played with Ronaldinho and Eto'o, and among them was jealousy.
"With Messi I do not see anyone jealous, but showing respect. Neymar, Leo respects, and has taken his role very well."
It underlines just what a great job manager Frank Rijkaard did with his Barcelona side a decade ago, transforming them from also-rans into Champions League winners.
He kept the pair's jealousy largely behind closed doors, and did not let it manifest itself on the pitch.
In 2005/06, Eto'o scored a superb 34 goals, while Ronaldinho scored 26 himself and provided 22 assists. Sensational.
While the jealousy could have spurred them onto compete against each other, imagine what they could have achieved had they actually got along...
images:© Hector Garcia