Rachel McAdams as Irene Adler -- FIRST PICS

Here are the first pictures of Rachel McAdams in hair and make-up for her character, Irene Adler, in Guy Ritchie‘s detective flick, Sherlock Holmes.

The 30-year-old actress was spotted in London on Thursday wearing brown shoes and pinstripe pants. Adler is a femme fatale from New Jersey who once outwitted Holmes (Robert Downey Jr.), earning his grudging respect.

Sherlock Holmes is expected to release October 2009.

10+ pictures inside of Rachel McAdams as Sherlock Holmes‘s Irene Adler…