Cheryl Cole, Nicola Roberts, Kimberly Walsh and Nadine Coyle are pulling out all the stops to ensure Harding doesn't falter.
Harding was treated for alcohol abuse and depression after splitting with fiance DJ Tom Crane in 2011, reported Sun Online.
"The girls have decided to ban alcohol altogether in support of Sarah. She's still dealing with her alcohol problem two years on and they've decided to ban it out of respect to her. It's only fair