I was 12 when Mrs Stromberg taught me at Nichols Junior High in Evanston, Illinois. Evanston was the fantasy of what a small American town should be. It had a drugstore where you could sit on swivel chairs - that 1950s American look. There was a tiny library. I would walk to school and there wasn’t a franchise in sight.

Mrs Stromberg was the only teacher throughout my entire education to say I was smart. Everyone else said I had no chance. She was the first one to say, “I don’t care what her test results are, I think she’s got something.” It was the first time I had ever heard a teacher say something positive about me.

How can I describe this woman? She had that kind of fat momma thing going on, you know? She had a loving quality to her. I remember her as the grandmother I never had. It’s not an exaggeration to say she was the first teacher to show me any sort of kindness. The rest were dictators.

Look up 475 as an SAT result; it’s the intelligence level of a house plant. That’s what I got and the teachers used to take pride in telling me how hopeless I was. But not Mrs Stromberg. She was a beacon of warmth when everyone else was cruel.

The teaching methods back then were awful. We had to memorise everything, and I can’t retain information unless I’m being creative. Unless I’m writing comedy. So I’d open up the encyclopaedia, copy things word for word and inevitably get busted for plagiarism. Mrs Stromberg knew that, but she thought there was intelligence in them there hills and she went looking for it.

Can I tell you about my least favourite teacher? My typing teacher. Get this: she told my mother that I reminded her of Nathan Leopold, the infamous murderer. I don’t know how she recognised that from my typing.

Mrs Stromberg once bumped into my mother in the street and said she always knew I was talented. I don’t know in what area, because I wasn’t. She found me funny, though. Everyone else saw it as rebelliousness, but she thought it was funny.

I actually got into trouble once because I put sardines under the light fixture so the school would smell. They didn’t know where it was coming from. Mrs Stromberg stood by me, even through that. What a woman. I think she might be dead.

I tell you who else was an inspiration: Virginia Snyders, the head of Guildhall [School of Music and Drama in London]. She was the first person to take an interest in my acting. She let me hoover her house. What I mean is, I couldn’t get into drama school, but the trade-off for my doing the hoovering was that she would teach me how to act. And, again, she was the first person to say, “You know what, you’re really good at this.”

It’s amazing, really, what a bit of positivity can do.

Ruby Wax was talking to Tom Cullen. Her book Sane New World is published by Hodder and Stoughton, priced at pound;8.99. Her nationwide theatre tour runs until 22 May. For more information, visit www.rubywax.net

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Ruby Wax

Born 19 April 1953, Evanston, Illinois, US

Education Nichols Junior High School, Evanston

Career Classically trained actor who performed with the Royal Shakespeare Company; stand-up comedian and writer