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TV Line reports that Atias will play Christie, the cardiologist girlfriend of Diana Barrigan (Marsha Thomason).
Christie will first appear in the season's third episode, when she is recruited to assist with the FBI's latest investigation. The previously-unseen character has been referred to in past episodes and is expected to recur in the future.
Atias previously played Inez in Starz series Crash and has also appeared in episodes of CSI: NY and Rules of Engagement.
Former 24 star Atkinson will also appear in the third episode as a tough magazine editor who is threatened when she refuses to back away from a controversial story.
The actress played Karen Hayes in the fifth and sixth seasons of 24 and recently featured in Criminal Minds and Gossip Girl.
White Collar will return to USA on June 7.
> White Collar exec teases third season
