The 59-year-old, who was the fourth Doctor's companion Romana in 1978, made a brief Walford appearance earlier this year as Charlie Slater's (Derek Martin) wayward Russian lady friend Orlenda.
Charlie - or Chorley as he affectionately became known - met Orlenda at the airport on his return from Madeira when his friendship with Brenda Boyle (Carmel Cryan) broke down.
The London cabbie quickly invited Orlenda to stay with him for a while, much to the dismay of Big Mo (Laila Morse), who quickly accused her of being an illegal immigrant. However, when confronted, Orlenda reluctantly confessed to Charlie that she was a con artist but couldn't go through with fleecing him because of his affable nature.
Charlie was subsequently left devastated when Orlenda left and resigned himself to a life of loneliness.
Speaking exclusively to DS about her time with the BBC soap, Tamm said: "I absolutely loved it. It's the Russian background [that got me the role]. My mother, despite spending most of her life in Estonia, was actually Russian.
"The director I worked with on EastEnders directed me on Brookside and he'd remembered this Russian background so that’s why he cast me - because they love to have authenticity where possible."
She added: "It was great to do and they were all lovely - very friendly and welcoming. It was a very happy experience and I absolutely loved it. Hopefully they’ll ask me back, which would be nice."
Tamm recently recently published the first part of her autobiography, titled First Generation.
> Click here to read our recent interview with Mary Tamm in full