(CNN)"Downton Abbey" star Michelle Dockery's boyfriend, business relations executive John Dineen, died Sunday after a long illness, according to news reports. "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," a spokesman told Britain's ITV News. Dockery generally kept her personal life private but said last year that she had "a wonderful man in my life from Ireland." Dockery plays Lady Mary Crawley on "Downton."