The former X Factor winner arrived in casual black trousers and a t-shirt but switched into a glamorous and elaborate royal purple ballgown. And we can't forget the crown!
We bet her daughters loved it!
Sam, 38, will star in this Christmas's Dick Whittington pantomime at the Aylesbury Waterside Theatre, playing the magical Fairy Bowbells.
She joins fellow X Factor alum Melanie Masson, who appeared on the ninth series of the show, and will star here as baddie Queen Rat.
The show begins from Friday, 11 December.
Meanwhile, singer Sam recently announced another stage appearance: her West End debut at the Lyric Theatre in London on 12 October.
She'll perform a one-off concert alongside special guests including Britain's Got Talent stars Collabro.
"I can't wait to take the stage in London's incredible West End and have the chance to perform some of my favourite musical theatre numbers," she said. "It's going to be a fantastic night with a few surprises for the audience!"