John Dineen and Michelle Dockery
John Dineen and Michelle Dockery were dating since 2014 after being introduced to each other by Allen LeechMatthew Stockman/Getty Images

John Dineen, boyfriend of Downton Abbey actress Michelle Dockery, died on Sunday at the age of 34. The London-based PR executive was diagnosed with a rare form of cancer and had returned home to Ireland to receive treatment at Marymount Hospice in Cork.

"The family is very grateful for the support and kindness they have received but would kindly request that they are left to grieve in private," read the statement issued by Dockery's publicist.

Dineen and Dockery were dating since 2013 and although guarded about her romantic life, Dockery revealed publicly in 2014, "I have a wonderful man in my life from Ireland. We were introduced by (Downton's Tom Branson) Allen Leech. That's all you need to know."

There were rumours of the two being engaged but neither confirmed the same. The Daily Mail, however, reported that the actress was planning her wedding and had shown off her ring to her fellow cast and crew.

The public relations company that Dineen worked for, FTI Consulting also put out a public statement. The firm's UK head of strategic communications, John Waples said, "John was an immensely valued colleague and friend and will be sorely missed.

"Our thoughts are with his fiancée Michelle, his family and friends, as well as our colleagues who were closest to him, and we ask for privacy for his family at this difficult time."

The actress who plays Lady Mary Crawley on the hit drama series cut short her US promotional tour for the final season of the show to spend time with Dineen and his family. She spent her birthday on 15 December in Ireland making arrangements for the wake and the funeral, which is expected to take place on 16 December.