The trio posed for a shoot with renowned photographer Rankin wearing nothing more than a Pudsey-esque paw print on their faces.
The images are being used to promote the brand new Children in Need event, which takes places on Friday, November 9.
"I was extremely honoured to be asked to get involved," Flack said. "While I was initially apprehensive to bare all at the shoot, it was a great experience."
Redknapp added: "Being able to encourage women to be empowered and confident is something I am so passionate about. Going Bearfaced is a really simple way to raise money for a great cause."
Members of the public are encouraged to collect sponsorship from friends, family and colleagues via BT My Donate, or pick 'BearFaced' as the event across most other digital sponsorship sites - https://mydonate.bt.com/events/bearfaced.
Every penny raised will go on to help change the lives of disadvantaged children and young people across the UK.
The Children in Need 2012 telecast airs on the BBC on Friday, November 16.