The character (played by Michelle Fox) will turn up in the emergency department for her first ever shift in this evening's episode.
However, the seemingly friendly and confident doctor is hiding a huge secret.
Actress Michelle told Digital Spy that Bea will have a “wandering eye” which will get her into trouble, before major details are unveiled.
Michelle explained: “She's very confident, she's very chatty and she's got a big mouth – which gets her into a lot of trouble.
BBC
No one really knows about her background and she comes across as if it's just her by herself
“She's got a bit of a wandering eye which also gets her into trouble as well. She wants to portray someone who is very confident, very happy and knows exactly what she's doing, but she has a lot to hide!
“I think people think they know a lot about her but they don't really know anything. As the episodes go on, she finds it more and more difficult to hide who she is.”
Michelle added: “She likes to hide behind her emotions, but as the stress of the job gets worse, she finds that increasingly difficult.”
Casualty series producer Lucy Rafferty also revealed last year that fans will discover there is “more than meets the eye” with Bea, and that viewers should expect massive plots.
BBC
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Michelle confirmed that no other character knows her background just yet, and Bea is not very forthcoming with information about herself.
She said: “I think in the first couple of episodes you see the Bea that she wants everyone to see. She always tries to bounce back – even when she gets into trouble.
“But she's an extremely emotional person and there is a lot more to her. She likes to bottle it all up inside and she doesn't tell a lot of people about herself.
“No one really knows about her background and she comes across as if it's just her by herself.”
BBC
Michelle added: “I don't think anyone realises just how soft she is on the inside because she really rallies to try and not let people see that.
“The jokey, jovial stuff we see between her and Rash is something she hides behind.”
What is Bea really holding back and hiding from her colleagues?
Casualty continues tonight on BBC One at 8.20pm.
