Shirley Maclaine joined Downton Abbey as Cora's American mother Martha Levinson.
She appears in two episodes were she clashes with Dowager Countess of Grantham (Dame Maggie Smith).
The Hollywood star revealed that filming at Highclere Castle in Hampshire was a dream come true.
She told the Sunday Express: "Now that's a once in a lifetime experience to shoot in such a hallowed place.
"I enjoyed very, very much that castle and the grounds and the past and the haunting."
However, she admitted that she was not a fan of the Downton costumes.
The 78-year-old actress has described herself as a "jogging pants and tennis shoes" type of woman.
Discussing the costumes in the period drama, Shirley said: "I hated to put all that stuff on, I'm not one for wardrobe."
MacLaine, won the best actress Oscar in 1983 for Terms Of Endearment and was nominated for a further six Academy Awards.
This article is powered by Well Contented Ltd
More About Downton Abbey
- Maggie Smith has 'brilliant storylines' in Downton Abbey
- Downton Abbey star Lesley Nicol enjoys being in US
- Downton Abbey causes Matt Damon marital strife
- George Clooney not good enough for Downton Abbey
- Downton Abbey producer says not plans to end drama
- Downton Abbey Christmas Day Special: all the action unveiled
- Paul Giamatti found filming Downton Abbey 'bizarre and English'