Mr. Lindsay-Hogg, 82, lives with his wife, Lisa Ticknor Lindsay-Hogg, a former fashion model and casting agent, in a narrow cream-colored house in this river town nestled into lush green hills. The rooms have a lived-in feel, with book stacks rising from table tops and the walls blanketed with paintings, many of them scavenged from flea markets, and photos from his varied career. “I am the maximalist,” he said. “Lisa is the organizer.” The couple has lived here less than two years. During lockdown, they rented a rock-star-style tour bus and fled Los Angeles, where they had lived since they were married in 2002. California’s wildfires were part of what drove them out. “The sky was yellow,” Mr. Lindsay-Hogg said. “You could taste the soot.” The move meant abandoning a city where he had deep ties. Although he was born in Manhattan and educated at Choate, the Connecticut prep school, he spent six years of his childhood in Hollywood, mingling with William Randolph Hearst, Olivia de Havilland and Humphrey Bogart. His mother was the actress Geraldine Fitzgerald, who starred opposite Laurence Olivier in William Wyler’s “Wuthering Heights” in 1939. His father — at least, according to his birth certificate — was Sir Edward Lindsay-Hogg, a baronet of Rotherfield Hall in East Sussex, England. The younger Mr. Lindsay-Hogg inherited the title upon the elder’s death in 1999. The question of paternity has long hovered over him. His mother, born in Ireland, made her American stage debut opposite Orson Welles in a 1938 revival of George Bernard Shaw’s “Heartbreak House.” The production was directed by Mr. Welles at the Mercury Theater, the New York repertory house he had co-founded. When Mr. Lindsay-Hogg was a teenager, his mother told him of the rumors that Mr. Welles, best known for his 1941 film classic “Citizen Kane,” was his biological father. “It certainly played into my life growing up, partly because of the way I look,” he said. “I was heavy when I was young, and Orson was heavy. I have a round face; he had a round face. I didn’t look like Edward Lindsay-Hogg, who, if anything, looked more like, say, Jeremy Irons.” At 19, Mr. Lindsay-Hogg had a small role in Mr. Welles’s stage production of “Chimes at Midnight” in Dublin. “I knew him over the years, and he’d pop up every so often,” he said. Shortly after the run, Mr. Welles offered him a job in a London production of Eugène Ionesco’s “Rhinoceros.” “He said, ‘I’ll call you in a couple of days and you can come over,’” Mr. Lindsay-Hogg recalled. “I then did not hear from him for five years.” Decades later, his mother, who had Alzheimer’s at the time, gave a cryptic confirmation that Mr. Welles was his father — then seemed to contradict it. Mr. Lindsay-Hogg got an answer when he spoke with Gloria Vanderbilt, a friend of his mother’s whom he had dated in the 1980s, while working on his 2011 memoir, “Luck and Circumstance.”