TV Line says that Cohan, who is currently starring as Rose in The Vampire Diaries and previously appeared in Supernatural, has signed up for a major recurring role in the show.
She is expected to play Vivian, a beautiful socialite who is studying history at Oxford. However, Vivian is said to be the daughter of a criminal mastermind.
Meanwhile, Givens has landed a multi-episode arc as a "powerful and controlling" agency boss who makes an offer to Casey (Adam Baldwin). The actress has previously appeared in shows including House of Payne and My Parents, My Sister & Me.
Chuck airs on Mondays at 8/7c on NBC.