South Korea's four-time Olympic swimming medallist Park Tae-hwan has been banned for 18 months by world swimming body FINA for failing a drugs test.
The 25-year-old tested positive for a banned anabolic steroid at an out-of-competition test in September last year.
Park won 400m freestyle gold and 200m freestyle silver at the Beijing 2008 Olympics, becoming South Korea's first Olympic swimming medallist.
He also won silver in both events at the 2012 London Olympics, along with 400m gold in the world championships in 2007 and 2011.
The positive test sent shock waves through the sport in South Korea where prosecutors last month announced charges against a doctor for giving Park an injection without disclosing it contained the banned steroid testosterone.
The swimming star - nicknamed "Marine Boy" - blamed the injection, administered last July, for a positive drug test on urine samples he provided prior to the Asian Games in Incheon, Korea, where disappointingly for his home fans he had to be content with three bronze medals.
FINA said that Park's results from September 3 onwards will be annulled and prize money forfeited, meaning he will have to return the medals he won at last year's Asian Games.
The ban for his first doping violation will run until March 2, 2016 which will in theory allow him to compete at the Rio Olympics later that year.