Dame Kiri Te Kanawa said she was so happy to land the role of famed opera singer Dame Nellie Melba in Downton Abbey she named her new pet dog after the hit show.
The star said she "couldn't say 'yes' fast enough" when she was offered the guest spot in the new series.
She plays the real-life Australian singer who was one of the biggest singing stars of the early 20th century.
Dame Kiri said she studied a diary of Dame Nellie's performances over 30 years to get into the role and chose suitable songs for the part which sees her perform at a party at the fictional country house.
She performs several songs including SONGS MY MOTHER TAUGHT ME which was regularly performed by Dame Nellie.
Dame Kiri said: "We've got a recording of her doing it so we tried to copy it and it's very beautifully done and very special so we had to put that one in."
The singer said she was "not sure" she really acted in her scenes with the cast which includes some spoken lines as well.
She said: "I was trying to stay true to the character because as (show writer) Julian Fellowes said 'she's the only true character' that actually lived."
Producer Gareth Neame said her performance had gone down a storm, adding: "It was the sight of all these tough electricians and grips and all the people you see on a film set with tears in their eyes and wiping a tear away as they heard you. It was quite a special day."
Dame Kiri admitted she was nervous before she arrived on set, saying: "It was a long day but I made it longer by staying up most of the night."
She said: "The most incredible thing is I took my two dogs along and Lady Carnarvon didn't want those anywhere near the place but the thing is during the time I was expecting doggy number three and she's called Abbey as in Downton.
"She's my little Downton prize".
The new series, which starts on ITV later this year, is set in 1922 and sees the characters dealing with the aftermath of the death of Matthew Crawley (Dan Stevens).