Olympic swimming champion Michael Phelps has been arrested for drink-driving after he was stopped for speeding in Maryland.
Phelps was pulled over at about 1.40am on Tuesday in Baltimore after an officer clocked his white 2014 Land Rover driving 84mph in a 45mph zone.
He "was unable to perform satisfactorily a series of standard field sobriety tests", police said in a statement.
Phelps' Land Rover was still parked along the motorway on Tuesday. Pic: CBS
Phelps was arrested on charges of driving under the influence (DUI), excessive speeding and crossing double lane lines.
The 29-year-old, who police described as "co-operative", was later released.
Authorities have not said whether a blood-alcohol level test was administered.
Phelps tweeted about the arrest on Tuesday afternoon, writing: "I understand the severity of my actions and take full responsibility.
"I know these words may not mean much right now but I am deeply sorry to everyone I have let down."
The arrest was Phelps' second drink-driving charge in Maryland. The Baltimore County native was charged with DUI in 2004. In 2009, Phelps was briefly banned from competing after a picture emerged that appeared to show him inhaling marijuana from a pipe. Phelps is the most decorated Olympian of all time with 22 medals, including 18 golds.
He announced in April that he was coming out of a near two-year retirement.