Sienna has a laugh with French and Saunders for Comic Relief
Sienna Miller has joined French and Saunders for a rip-roaring Mamma Mia spoof in aid of Comic Relief.
The Edge of Love actress plays young Sophie in the sketch called Gimme Gimme Gimmick, which will be shown on BBC1 on Friday night.
Joanna Lumley, Alan Carr, Phillip Glenister and Matt Lucas also join the comedy duo for what is going to be their last ever sketch together.
With crimped, tousled hair extensions and her natural golden glow, Sienna looked every inch the gorgeous beach babe as she larked around with her comedy co-stars.
The Comic Relief organisers have really pulled out all the stops this year, with Cheryl Cole and her fellow celeb pals already raising a whopping £1 million for the charity when they successfully climbed Mount Kilimanjaro earlier this month.
We bet they'll be hoping to raise lots more money, money, money on Friday night!
See exclusive behind-the-scenes footage below: