Named Red Velvet, the aircraft took off from London Heathrow on September 10 bound for New York JFK.
It features a new Loft area in the Upper Class cabin where passengers can meet, drink and dine together.
All seats in the redesigned business class cabin face towards the windows and have enhanced privacy, adjustable mood lighting and 18.5-inch screens.
Upper Class passengers will also be able to order food and drink when they want it via their IFE screen. Wifi access is priced at £20.99 for the duration of the flight.
Virgin has ordered 12 of the aircraft model with all of them scheduled to join the fleet by 2021.
The first four A350s will go into service by the end of 2019 all initially flying between Heathrow and JFK.
Los Angeles will be Virgin’s second destination to welcome A350s into service, from 2020.
Flights are now on sale for Virgin’s services between Heathrow and Sao Paulo, Brazil, which commence on March 29 next year. Return fares in economy start from £578, in premium economy from £1,048 and Upper Class is from £1,998.