Merna, who plays Carmel McQueen in the soap, has been engaged to her partner Ian Minton since 2007.
She explained that although they haven't set a date for the wedding yet, she would like her Hollyoaks colleagues to be involved.
"The whole cast are really, really close but obviously [I'm closest to] Jennifer Metcalfe, Nicole Barber-Lane and Claire Cooper," she told Now. "They're all going to be bridesmaids at my wedding."
Merna recently admitted that she "can't be bothered" to plan her nuptials.