The 33-year old Bulgarian, who has called time on his career after a 14-month fight with leukaemia, arrived at Parkhead from CSKA Sofia in 1999 and achieved plenty of success with the Hoops to whom he is eternally grateful.
"When I was a young player at CSKA Sofia the good life was all I was interested in," he said.
"Celtic came in for me (in 1999) and I moved to Glasgow, to a new world. I didn't speak the language and I knew nobody. Fortunately, I met people who helped me to turn my life around.
"I came to know great teammates who showed me the proper way, the way I had to be if I was going to be a serious professional.
"Then something crazy happened, something I thought was just a cold but turned out to be something life-changing.
"It is with a heavy heart I am announcing my retirement from the game."