The "Lord of the Rings" beauty has been largely single since splitting from British rocker Royston Langdon, the father of her son Milo, in 2008 after five years of marriage, reported Daily Star.
The hook-up comes two nights after the pair attended the same post-Emmys party at the Sunset Towers hotel in West Hollywood on Sunday, where they were spotted chatting to Cumberbatch's "Star Trek Into Darkness" co-star Zachary Quinto.