The 30-year-old joined the East Londoners in 2009, but after just a year in England he returned to his native Italy with Brescia.
"I had a wonderful experience in the Premier League and would recommend it to anyone," The Mirror quotes the now-Bologna striker as saying. "You get to work seriously and as a professional, but you are also free to live your own life. Perhaps the only regret of my career was leaving London."
Diamanti scored eight goals during his stint at Upton Park.