The 26-year-old was removed from the MTV show in 2013 after she was accused of making a racist remark on camera, but she will return for the Birthday Battle special.
Speaking to Daily Star, she said of her exit: "It was the biggest mistake of my life. It's the biggest regret and I am sorry. I had the best job in the world and to lose it was awful.
"We were just ordinary kids from Newcastle who had nothing and suddenly we were on the best show on TV. Everyone who has stepped into that Geordie Shore house has had their lives changed for the better. Coming back was amazing and I would give anything to return to the show full-time."
Sophie was axed in 2013 after being caught making an offensive comment on camera. An MTV rep at the time said: "After an incident last week, Sophie Kasaei was removed from Geordie Shore pending further investigation into alleged offensive behaviour.
"MTV and Lime Pictures have now taken the decision that it is inappropriate for Sophie to return to the show. We will be reiterating to the remaining cast members that offensive behaviour will not be tolerated."
Sophie's exit was not aired on the show, instead viewers watched as the housemates woke up to find Sophie's bed empty and a letter explaining she'd had to leave.
But now she'll return to the Newcastle house for the Geordie Shore: Big Birthday Battle special, which kicks off tonight at 10pm on MTV.
In scenes to air tonight, we'll see Charlotte Crosby declare: "This has got to be a dream. What the f**k? Sophie has just walked through the f**king door. It means so much to us that Sophie is back. She's the first friend I made in the house and to see her walk through the door, I just can't describe how happy I am."
Celebrating five years of the programme, old stars will return alongside current castmembers in a competition to throw the best parties.
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