Llewelyn, known by colleagues as Mr Taittinger UK, had been a stalwart of the drinks trade for nearly 40 years but not been well for some time.
Justin, who lived in Sleaford, Lincolnshire, was the son of Desmond Llewelyn, who played Q in 17 James Bond films
He attended the Hatch Mansfield Christmas party the night before he died.
The distributor had worked with him for 24 years and said he played a pivotal role in the development of the sales and image of Champagne Taittinger across the UK.
Patrick McGrath, managing director at Hatch Mansfield, said: “He was a man of many talents with a wicked sense of humour and I for one am going to miss him dreadfully.
"My thoughts and prayers are with his wife, Claire and daughters Rosamund and Charlotte. They are being incredibly strong and are relieved that his suffering is over and he is now at peace.”
As well as his knowledge of Champagne, Justin was also one of the UK’s leading equestrian commentators working at such well-known events as, Badminton, Blenheim, Burghley and the Gatcombe National Championships.
Pierre-Emmanuel Taittinger, president of the Champagne House, said: “Justin Llewelyn had a Champagne soul and attitude. Friendship, elegance, generosity and a natural sense of humour.
"As an ambassador of the French culinary traditions he was a real epicurian and on top of it a marvellous Champagne compagnon not only for the Taittinger house and family but also for the Champagne fraternity as general consul of the Ordre des Coteaux.
"Like his father he was also a great and passionate actor, but in the field of Champagne, for the best bubbles of our dreams and lives.”