The on-hiatus girlband are making plans to celebrate their 10th anniversary next year with a reunion tour and Sarah, 29, is excited at the thought of performing with Cheryl Cole, Nadine Coyle, Kimberley Walsh and Nicola Roberts again.
She said: "I'm looking forward to just getting back together to do all the old songs, all five of us in front of a big screaming audience. There's chemistry when we're all together on stage and I miss that."
Although they haven't made any solid plans - as all the members have been busy with their individual projects - Sarah is hoping the temporary reunion will lead to something more permanent.
She said: "We've not confirmed anything, we're still talking about it. I'd like to do an album and a tour."
Although Sarah has branched out into modelling and acting during the band's break, she admitted it can be terrifying doing these without her bandmates.
Speaking about her recent catwalk debut, she added to Look magazine: "I was literally shaking. I didn't have my girlies around me and they're like my safety net. It was amazing, nerve-wracking and exciting."