Ferne will play Myrtle Wilson in Linnie Reedman and Joe Evans' musical Gatsby at the Union Theatre in April this year.
The production, which is a a musical version of F. Scott Fitzgerald's classic The Great Gatsby, will run between 6th and 30th April 2016.
Ferne, who started rehearsals this week, told Mail Online: "I'm still nervous now I've got the part! I've got to earn my stripes and I'm willing to put the work in."
Having recently become an entertainment reporter for ITV's This Morning, Ferne came in third place on series 15 of I'm A Celebrity Get Me Out Of Here!, which wrapped up in December.
At the beginning of this year, she revealed plans to pursue acting and she had even previously told her I'm A Celebrity campmates that she dreams of a role in something like Downton Abbey.
Having previously teased a film role and revealed she was taking acting lessons, Ferne told Reveal last year: "I've always been a bit of an actress growing up. I was in plays, I went to theatre school and I studied theatre studies at A-level. Acting has always been what I wanted to do, but obviously you take different paths."
Ferne bowed out of TOWIE earlier this year to focus on other projects, but promised she wouldn't stay too far away.
Announcing her exit from the ITVBe reality show in February, she said: "I have been super busy since I've been back from Australia, which means you won't be seeing as much of [me] on The Only Way Is Essex. However, if any of my friends ever need me or need my advice I will make sure I am back to Essex to help them."
Ferne appeared in an episode earlier this month in a scene with co-star Danielle Armstrong, and she also made a brief cameo in the first episode of the new series when Danielle and Bobby Noris filled her in on all the Gran Canaria gossip via FaceTime.
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