The Carly Wicks actress, who returns on Thursday (September 6) to help off-the-rails mother Shirley (Linda Henry), revealed that she accidentally lost control of a truck and ran over electrical wires.
Speaking to The Sun, she explained: "When I read the script and it said Carly would drive around Albert Square in a big truck, I thought, 'How am I going to do that?'
"The Square is tiny so it's not easy to manoeuvre a great big truck around it, especially when you are as small as I am.
"I put on Carly's 5-inch heels and got in the truck but as I started the engine and tried to drive in the heels I couldn't control it and ran over a load of electrical wires and almost blew the Square up.
"Everyone was waving at me like crazy to stop the truck because I'd cut off all the cameras and lighting equipment."
The 29-year-old admitted that producers ultimately hired a stunt double to record the scene, fearful that her driving would lead to further damage to the show's set.
She added: "It's just a good job I didn't crash into The Queen Vic. We had to shoot the scene again but they were so nervous about letting me back in the driving seat, they had to get a double to do it instead.
"Nobody is supposed to know - but when you see the high heels first step out of the truck onto Albert Square, it isn't actually me. I think everyone on set was quite relieved for their own safety after I got out."
Kellie Shirley, who is only making a brief comeback, recently told Digital Spy that she is keen to sign a long-term contract with the soap.
> Read our full interview with EastEnders star Kellie Shirley here