Wacky American comedian and actor Kate McKinnon, known for her years on SNL and her recent ‘Weird Barbie’ portrayal in the eponymous hit movie, has not been on social media for seven years because of the negative impact it had on her wellbeing.

"I can’t take the heat, so I got out of the kitchen. I just don’t want to know what’s the worst thing that everyone thinks about me. I’d rather just not have that in my brain. I think it’s damaging to everybody to have access to that," says the amiable comedian, on a whistlestop visit to London to promote her debut children’s novel The Millicent Quibb School Of Etiquette For Young Ladies Of Mad Science.

For a decade, the Emmy award-winning New Yorker, 40, was a regular on Saturday Night Live, the US sketch show where she performed impressions of Hillary Clinton, Ellen DeGeneres, Jodie Foster and Penelope Cruz, among others, and transitioned to Hollywood movies including Ghostbusters and Barbie.

"I used to read reviews of Saturday Night Live, I’m ashamed to admit," says the comedian and writer, who left the TV show in 2022.

"People told me when I got the job, ‘Don’t read reviews’ and I said, ‘No, I won’t’, and then I did, religiously. And I really wish I hadn’t. At times they were instructive – I actually learned from reading criticism and I think I did grow, but it also hampered me in a way."

To maintain good mental health, she says: "I do not look on the internet. I have not Googled myself or read a Tweet or anything for about seven years."

She fears that young people have a harder time now than she did when she was growing up, because of social media.

"I would hate to be a young person when feedback you’re receiving about yourself – not just in person from your peers but in written form from your peers and strangers – is permanent, in that the internet is indelible.

"As an adult I’ve barely been able to handle reading comments about myself on the internet. It’s not appropriate for a developing brain to have access to what everyone thinks of them, and I’m talking about social media."

Her madcap children’s novel centres on three oddball sisters and a good-hearted mad scientist Millicent Quibb, who set out to save their old town, Antiquarium, from a cohort of evil mad scientists who are plotting dastardly deeds.

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It’s funny and fantastical, featuring all manner of strange creatures, from exploding jellyfish and leech-eating flowers to a murderous giant worm called a kyrgalops.

She hopes the book will help the "next generation of weirdos" feel less alone and that they do have something to contribute, sentiments she can relate to.

The eldest daughter of an architect and a social worker, McKinnon grew up on Long Island. From a young age she had a talent for doing funny voices and a musical gift, playing piano, cello and guitar, but recalls feeling like an outsider.

"As a child I had a lot of bizarre interests and I loved science and nature. I would take home the clam and mussel shells from when we went out to eat, put them in the bathtub and pretend I was in the sea."

She kept strange pets, including a tank of Madagascar hissing cockroaches which she would allow to crawl on her hands.

"They were my little buddies. I would take them out and talk to them. I didn’t name them because they all look the same and I couldn’t keep track, but I was just in love with the world and felt out of step with my environment.

"I was made fun of at school, I mean, I don’t know a 12-year-old who wasn’t made fun of at school. I was slightly bullied," she recalls, playing it down as she says even the cool girls seemed to have had a hard time when they were 12.

The loneliness ended when she found a friend "who also liked lizards". "I wasn’t lonely at home, thankfully, because my parents were both funny and oddballs in their own right, and my sister (Emily, also a comedian) as well. But out there in the world I got the messages that we all get about keeping yourself contained and fitting in.

"Once I found my tribe, a group of really weird girls, and we just got into little anodyne, analogue bits of mischief in my town and it was wonderful."

Her book reinforces the message that it’s ok to be different.

"I think it’s so important to reach out to young people and let them know that the thing that is bizarre or odd about them, or the thing that they feel makes them different, is the thing that will become their greatest asset when they grow up. I know that’s true for myself."

At university, McKinnon starred in several stage productions and helped found a musical improvisation comedy group before being cast in The Big Gay Sketch Show on a TV network which focused on an LGBTQ+ audience. She later secured her place on Saturday Night Live, becoming the show’s first openly lesbian cast member.

McKinnon has seamlessly transitioned from TV comedian to Hollywood star, having appeared in the Ghostbusters reboot in 2016 and the Richard Curtis movie Yesterday while she was still doing her TV sketches, and most recently Barbie, although she says she has always had more recognition from Saturday Night Live because it’s a cultural institution in the US.

"Both venues (small and big screen) have been very rewarding in their own way. Being in a big blockbuster movie feels like really participating in the culture, but also being on a sketch show that allows you to speak about things so immediately also feels like a way of being part of the conversation."

She wasn’t surprised that the Barbie movie was such a hit because she knew the director Greta Gerwig (they went to college together) and says she’s a genius.

"I like to do a somewhat niche thing, so it’s not every day that a character like Weird Barbie pops up. I couldn’t have written a character for myself that was more my story."

Away from work, she still resides in New York State, but now lives in the countryside where she’s become an avid gardener and woodworker.

"These activities are very grounding. You’re engaging with physical materials in the world – wood and plants. I eat what I grow. I try to stay connected to the natural world.

"It’s on a swamp and I have a lot of interesting creatures running around such as groundhogs, snakes, and turtles that lay eggs in the spring. The grossest one is an invasive species of giant crayfish that burrows in the lawn, called lawn lobsters. They bite – they are very aggressive.

"But I feel less intimidated by the lawn lobsters than by strangers’ opinions."

Her children’s novel describes creatures far more outlandish than these, and she has almost finished the sequel, which will see the same characters on another adventure.

"My greatest wish for kids who read this book, or just children in general, is to go outside and reconnect with the real world, with nature, instead of the world that exists that we’ve built on the internet."

The Millicent Quibb School Of Etiquette For Young Ladies Of Mad Science by Kate McKinnon is published by HarperCollins Children’s Books. Available now