11 famous people who prove you don't need good grades to be successful

Young simon cowellYouTube / screenoceanSimon Cowell left school with just one O level.

When you’re in the middle of exams, it can feel like they’re taking over your whole life.

From the ages of 15 to 18, your summers seem packed full of revision and the existential dread that you won’t get into the university you want to.

However, plenty of people who we now consider to be incredibly successful didn’t actually do too well at school.

Everyone knows the stories about how Bill Gates and Mark Zuckerberg dropped out of university to become two of the richest people in the world, but many other successful people didn’t even get that far.

Scroll down to see how academie wasn’t suited for 11 highly successful people — and how it didn’t matter anyway.

Richard Branson left school at 16.

Branson never had much interest in school, dropping out at 16 to start his first business -- a magazine called 'Student.'

His headmaster, Robert Drayson, told him he would either end up in prison or become a millionaire, according to The Telegraph.

He achieved the latter, and now the Virgin Group owns over 200 companies in 30 countries around the world.

Simon Cowell passed barely any exams.

In the music industry, very few opinions matter more than those of Simon Cowell. He wasn't always the top dog, though. Cowell left school with just one O level -- the equivalent of GCSEs -- and dropped out at just 16.

He began his career working in the mailroom at his father's company EMI Music Publishing, according to Biography.com. There, he was eventually promoted to a talent scout, then left during the early 80s to form E&S Music with his boss Ellis Rich.

After a few short-lived successes with several companies, Cowell made his name at BMG Records where he sold more than 150 million records and 70 top-of-the-chart singles in the UK and US.

Drew Barrymore quit school after rehab.

Drew Barrymore is now an incredibly successful actor, producer, and businesswoman. However, she had a turbulent childhood after being sucked into the acting industry at just three years old.

She was in rehab by her 13th birthday, according to The Guardian, and decided not to carry on with education when she came out.

Despite all this, she turned things around and founded production company Fower Films in 1995, which was responsible for 'Charlie's Angels' and 'Donnie Darko.'

She is also now an Ambassador Against Hunger for the UN World Food Programme.

Lord Alan Sugar has 1 GCSE.

Star of The Apprentice and Amstrad founder Lord Sugar is worth about £1.4 billion. However, he didn't get there by working hard at school.

According to biography website thefamouspeople.com, Lord Sugar started earning money when he was just 12 years old. He dropped out of school with just one GCSE but it didn't stop him setting up his own business Amstrad at 21 years old.

Carey Mulligan was rejected from drama school.

Carey Mulligan is now an Oscar-nominated actress, but when she was a teenager she was turned down by Rada, Central, and Drama Centre London, according to The Guardian.

'But fair enough -- I wasn't very good,' she said. 'I went in and performed a monologue from 4.48 Psychosis by Sarah Kane, who subsequently killed herself. I was 17 years old, this incredibly well-adjusted, happy person. Nothing bad had happened to me. And I was trying to conjure all this pain and drama. So they were like, 'Who's this pretentious public-school kid trying to trick us?''

In 2005, she met a screenwriter, Julian Fellowes, who put her in touch with a casting agent. Mulligan then landed her role in Pride & Prejudice, which kick-started her career to become one of the UK's most promising young film stars.

Cheryl was a terrible student.

Cheryl -- formerly Cheryl Tweedy and Cheryl Cole -- was vaulted into stardom almost overnight when she appeared on 'Popstars: The Rivals.' The program created one of the most successful girl bands of all time, Girls Aloud.

Before fame, Cheryl was a feisty teenager whose temper got her into trouble with teachers, according to the Evening Standard.

'I was awful. They used to throw me out of class,' she said.

Benedict Cumberbatch got lazy after his GCSEs.

Benedict Cumberbatch has achieved great success as an actor. He went to Harrow, and admits he had a pretty good start in life. However, his interest in academia decreased after his GCSEs.

'I did sort of blow my GCSEs out of the water. I couldn't believe it and neither could my teachers,' he told The Metro. 'And then there was a lot of pressure on me to achieve an Oxbridge level of brilliance at A-levels. But then adolescence came late and I discovered girls, pot, and all sorts of other things, so I got a bit lazy. That stagnated my growth a bit as far as being academic.'

Since getting into acting, Cumberbatch has earned Golden Globe and Oscar nominations.

Russell Brand was a trouble-maker at school.

According to Biography.com, Russell Brand was kicked out of a boarding school for having girls in his room. He was also branded a 'waste of space' by one teacher.

At age 16, Brand went to London to study at the Italia Conti stage school. His teachers noticed he was talented, but he started experimenting with drugs and was kicked out 'for smashing things up, crying and cutting myself, breaking down in tears all the time.'

He battled with addiction for much of his career, but managed to be successful regardless. He is now one of the most famous comedians from the UK, and has also had success as a radio and TV presenter, as well as some acting roles.

He's caused his share of problems along the way, most memorably when he and Jonathan Ross made a series of prank calls to the Faulty Towers actor Andrew Sachs in 2008.

Steven Spielberg was rejected from film school.

Steven Spielberg is arguably the most famous director in the world, being the brains behind 'E.T.,' 'Jurassic Park,' 'Indiana Jones,' and 'Gremlins.'

According to Biography.com, Spielberg was an amateur filmmaker as a child. However, when he was older, he was rejected from the University of Southern California School of Theatre, Film, and Television three times. It didn't prevent him from achieving world-wide acclaim, though.

Spielberg returned to school in 2002 to earn his BA, 35 years later, as a thank-you to his parents.

'And as a personal note for my own family -- and young people everywhere -- about the importance of achieving their college education goals,' he said in a statement.

Jeremy Clarkson got two Us.

Most years on results day, Jeremy Clarkson reminds everyone on Twitter that he wasn't particularly academic.

It goes along the lines of: 'If your A-level results aren't joyous, take comfort from the fact I got a C and two Us. And I have a Mercedes Benz.'

Despite this, he managed to become one of the most popular TV show hosts in the UK on 'Top Gear,' and now 'The Grand Tour.'

Cameron Diaz dropped out at 16 to pursue a modelling career.

Jason Merritt/Getty Images

Cameron Diaz, one of Hollywood's most sought after actresses, dropped out of school at age 16 to follow a modelling career, according to the IBTimes.

From some success with modelling, she landed her first acting role and is now one of the highest-paid actresses in the world.

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