Susan's announcement comes as One Chance - the biopic of fellow BGT star Paul Potts - was released in cinemas last week.
Speaking at a press conference in London to announce the release of her Christmas charity single, 'O Come, All Ye Faithful,' Susan said: "There are plans in operation for that, but that's for later on."
The 52-year-old Scottish singer later told reporters to "watch this space" for more announcements.
Music mogul Simon Cowell also spoke of Susan in a recorded message at the press conference and said he was "proud" of the star. He added: "No one of all the people I've met has a bigger heart than you."
Susan rose to fame after singing a remarkable rendition of the Les Misérables song, 'I Dreamed A Dream' at the BGT auditions in 2009. She reached the finals and came in second place, losing out to dance troupe Diversity.
Despite not winning the show, Susan went on to become an international singing sensation, and topped the charts with the release of her debut album, I Dreamed A Dream. The life story of Susan was also turned into a stage musical last year.
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Watch Susan's BGT audition in the video below: