The 35-year-old is expecting her second child with fiancé Jade Jones, and said a new baby always brings her closer to Victoria Beckham, Geri Halliwell, Mel B and Mel C.
She told STV: 'Because we're all so busy we don't get to see as much of each other as we'd like but when something like this happens the bond we have shines through. It's like a sisterly relationship and that will always be there. In fact, Scarlet [Mel C's daughter] and Cruz [Victoria and David Beckham's son] have birthdays in a few days so it's a great excuse to get together.'
The star added: 'Because Victoria and I are pregnant we talked about that for a bit then I said, 'I do have some other exciting news' and I held up my ring. They jumped out of their seats and hugged and kissed us.'