Una Stubbs, the veteran British actress best known to American audiences for her role as Mrs. Hudson, the landlady to Benedict Cumberbatch’s Sherlock Holmes in the BBC series “Sherlock,” died on Thursday at her home in Edinburgh. She was 84.

Her death was confirmed by her agent, Rebecca Blond.

Ms. Stubbs was a recognizable face in Britain, where she had appeared in comedic and dramatic roles onstage, onscreen and on television for more than half a century, including in the long-running soap opera “EastEnders” and the sitcom “Till Death Us Do Part.”

American television viewers knew her best as Mrs. Hudson, the motherly landlady to Sherlock Holmes in “Sherlock.” The show, which aired from 2010 to 2017, was an international hit, and Ms. Stubbs turned Mrs. Hudson into a fan favorite by making the character a cheerful foil for the show’s darker themes.

The landlady was a bit of a phantom in Arthur Conan Doyle’s famous stories about Holmes, on which the show was based. So Ms. Stubbs and the show’s creators built Mrs. Hudson into a comedic parental figure with a checkered past.

“I am the mother of three sons, so I thought that would be a good angle to go on,” Ms. Stubbs told The New York Times in 2016. “I once told Benedict that my sons go straight to the fridge and make themselves sandwiches, and he did that in one episode.”

She added that the creators of “Sherlock,” Mark Gatiss and Steven Moffat, “have made me more saucy now, and a bit grubby, which I enjoy.”

Mr. Gatiss echoed that statement when he said of Ms. Stubbs on Twitter on Thursday that “mischief was in her blood.”

“We were so blessed that she became our imperishable Mrs. Hudson,” Mr. Gatiss said.

Una Stubbs was born on May 1, 1937, in Welwyn Garden City, England, north of London, the second of three children of Angela and Clarence Stubbs. She was raised in Hinckley, in Leicestershire. She told The Guardian in 2013 that one of her earliest memories was hiding under a dining table as the area around her childhood home was bombed during World War II. Her father, who was known as Clarry, served in the Home Guard in London during the war, she said.

Ms. Stubbs trained as a dancer, and in the 1950s appeared in advertisements for Rowntree’s, a British candy company. She would later learn that her paternal grandfather, whom she never met, had been a confectioner for the company in York, England.

Her breakout role was in the 1963 film “Summer Holiday,” a musical starring Cliff Richard, as a singer in a traveling musical trio. Other television credits include “Fawlty Towers,” “Keeping Up Appearances,” “Call the Midwife” and “The Worst Witch.”

She is survived by her sons Christian Henson and Joe Henson, both of whom are composers and musicians, and Jason Gilmore, as well as six grandchildren.

Her marriages to the actors Peter Gilmore and Nicky Henson ended in divorce, and Ms. Stubbs raised her sons as a single mother. She told The Guardian that she spent most of her life “doing two jobs, motherhood and acting, and only being so-so at both of them.”

“And now,” she added, “I’m trying to do one job really well, with a bit of grannying thrown in.”