Michelle Williams flashed her pants when she wore a risqué dress at the premiere of Oz The Great And Powerful last night.
The floor-length Prada dress, which was split up to the waist, gave onlookers the chance to have a good look at her black underwear.
The 31-year-old actress, who plays Glinda the Good Witch in the Disney movie directed by Sam Raimi, accessorised the dress with Prada heels and a Kate Young for Target clutch.
Michelle followed the yellow brick road carpet into a movie theatre in Hollywood with fellow co-stars Mila Kunis, Rachel Weisz, James Franco and Zach Braff.
Mila has been discussing her relationship with Ashton Kutcher on TV in the US.
Oz The Great And Powerful, the prequel to The Wizard Of Oz, is released nationwide 8 March.
Michelle sizzled when she appeared in GQ Magazine posing as Marilyn Monroe to promote her movie, My Week With Marilyn.