LONDON ? British "Harry Potter" actress Maggie Smith fears taking to the stage again after suffering breast cancer, which left her bald during filming of the last Potter movie, she said in an interview Monday.

Oscar-winning Smith, who has been given the all-clear after two years battling the disease, told The Times newspaper how she was "knocked sideways" and now lacked confidence to go back to the theatre.

"It leaves you so flattened. I?m not sure I could go back to theatre work, although film work is more tiring. I?m frightened to work in theatre now. I feel very uncertain. I haven?t done it for a while," she said.

The 74-year-old told how she discovered a lump in her breast last year. "I had been feeling a little rum. I didn?t think it was anything serious because years ago I felt a lump and it was benign. I assumed this would be too.

"It kind of takes the wind out of your sails, and I don?t know what the future holds, if anything. I don?t think there?s a lot of it, because of my age -- there just isn?t," she said.

Smith -- who is something of a national treasure in Britain -- described how she managed to go ahead with filming of "Harry Potter and The Half-Blood Prince," in which she again plays Professor Minerva McGonagall.

"I was hairless. I had no problem getting the wig on. I was like a boiled egg," she said, adding that chemotherapy made her feel "horribly sick. I was holding on to railings, thinking ?I can?t do this?."

She said she plans to "stagger through" filming of the final Harry Potter film, "The Deathly Hallows," hoping to put her cancer battle behind her.

"The last couple of years have been a write-off, though I?m beginning to feel like a person now," she said. "My energy is coming back. Shit happens. I ought to pull myself together a bit."

Smith has won five awards from Britain's BAFTA film and television academy, and two Oscars, notably Best Actress for her role in "The Prime of Miss Jean Brodie" in 1969.