The tournament is Murray's fourth since undergoing hip resurfacing surgery in January and his first on a hard court.

The brothers, 32 and 33 respectively, played together to help Great Britain win the Davis Cup in 2015.

"They called us and said Andy really wanted to come back to DC and wanted to play doubles with his brother," said Mark Ein, Citi Open manager.

"We're putting a real focus on doubles at the event - it's a terrific piece of the competition and entertainment value for fans so we were thrilled he wanted to return."

The brothers played with different partners in the men's doubles at Wimbledon, with Jamie and Neal Skupski exiting in the first round while Andy and Pierre-Hugues Herbert reached the second round.

Andy Murray played singles in Washington last year and was reduced to tears after finishing his last-16 win at 03:02 local time.

He withdrew from his quarter-final against Australian Alex de Minaur set to take place later that day, saying it was "unreasonable".

Earlier this year, Murray said on Instagram he would "probably not" return to Washington after tournament director Keely O'Brien "rinsed him" by saying that as a "global role model" he should show it is "not ok to just give up".

Jamie Murray won the Citi Open doubles title last year with former partner Bruno Soares - a pairing that also won Australian and US Open titles.