Someone --give that girl a cheeseburger!

Actress Sienna Miller shows off her extremely thin frame as she romps on the beach in a white bikini while on vacation in Spain.

Sienna Miller: See more bikini photos

The British beauty -- who’s been hard at work promoting her new action flick, GI Joe: Rise Of the Cobra -- is enjoying some downtime, vacationing in Ibiza, on Thursday.

• TAGS

• Balthazar Getty
• bikini
• George Barker
• GI Joe Rise of the Cobra
• Ibiza
• Jude Law
• Sienna Miller
• spain