Harry Potter actress Smith has proved a huge hit with TV audiences as the catty Dowager Countess of Grantham, but long-running rumours suggest she is demanding behind-the-scenes.
Producer Rebecca Eaton, who works for American network PBS Masterpiece, said, "Maggie Smith is a handful, it's true. She's very difficult. She knows her worth, and she's tricky on the set, but she delivers when the time comes."
However, Smith's co-star Nicol, who plays cook Mrs. Patmore, insists the 77-year-old screen legend simply needs to rest between scenes due to her age.
She says, "Maggie's a professional, she does really well, working horrible, long hours sometimes for a lady that age.
"She has a rest between takes. That doesn't make her a snotty cow, it just means she needs a lie-down. She's not a diva."