The former Emmerdale actress admitted that she was "petrified" about working on the long-running soap.
She told Inside Soap: "I had to call my mum on the first day as I was too scared to drive to the studio.
"I felt sick, because it was the biggest deal ever. But once I got there I was fine. Everyone was lovely!"
Tamaddon added that she was more nervous about working on Coronation Street than Emmerdale because she only had one audition and one screen test for the role.
She explained: "I was petrified because it was all so quick!
"I had five auditions for Delilah (in Emmerdale), but with Andrea there was just one, then a screen test with Simon Gregson (who plays Steve) and Craig Charles (who plays Lloyd Mullaney) - and then I was offered the job!"
Tamaddon will take part in Dancing on Ice: All-Stars in the new year, which will see six former winners of the ice-skating series battling to keep their crown.
Coronation Street airs on ITV. Get the Inside Soap magazine on your iPhone or iPad