Anna stripped completely naked in Versailles, in which she plays royal mistress Madame de Montespan.
The actress is a fan of getting her kit off in real life too.
Anna took to Instagram last week to post a video of herself in the bath.
The 31-year-old was completely nude in the video but protected her modesty with some clever camera angles.
Sexy celebs share intimate bath snaps 
View galleryAnna didn't have any make up on and kept her brunette locks loose.
She captioned the video "Tan Boleyn".
No, we don't know what that means either...
Anna's fans were loving the risqué clip.
"I love you Montespan," one commented.
"You are an incredible actress! If you continue, you will be one of the greatest," another posted.
"Babe," a third said, followed by a heart eyes emoji.
The first episode of Versailles series two saw a pregnant Madame de Montespan completely naked after a sex scene with the king.
Viewers described the series as "sex and debauchery".
Versailles continues next Friday at 9:30pm on BBC Two.
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