The actress, who is best known for her role as Weatherfield's Michelle Connor, is one of five celebrity contestants still left competing in ITV1's new reality series.
Saturdays star Vanessa White reportedly annoyed show mentor Rolando Villazón last month by skipping a rehearsal for the programme. She has since been voted off.
Writing in her New magazine column, Marsh commented: "I know Rolando Villazón was angry when Vanessa White missed a practice session because she had commitments with The Saturdays, but there might be times I can't make it too as my Corrie schedule is about to get really hectic. At the end of the day, Coronation Street is my priority."
Marsh said that she appreciated all of the support she has received from Operastar viewers so far.
She added: "On a different note, have you noticed just how rude judge Laurence Llewelyn-Bowen is to me? I think he's flirting!"