With GCSEs and A-Level exam season just around the corner, millions of nervous students are busy revising and preparing themselves to put their knowledge to the test. It's no secret exams can be hard and passing them isn't easy.

For those struggling with their exams, it might bring some relief to know they aren't alone. There have been many successful celebrities over the years who failed their exams but are now doing very well for themselves.

From Sir Richard Branson to Simon Cowell, several celebrities who now inspire students didn’t actually achieve their original desired education. Below is a look at some of the most successful celebrities who didn’t pass their exams.

Sir Richard Branson

After having a turbulent ride studying, Richard Branson left school at 16. He claims his headteacher told him he’d either end up in prison or he’d become a millionaire.

A few years later, he launched his first business, a magazine named 'Student'. Presently, he owns Virgin Atlantic, one of the largest airlines globally and has a network of $2.5B.

Robbie Williams

Despite being predicted to earn As and Bs in English, History, and Geography, Take That star Robbie Williams ultimately floundered, failing all of his GCSEs in high school. Reflecting on his journey to the Mirror, Robbie remarked: "If I went back to uni, well before that, I would go back and get all of my GCSEs – I failed them all."

Jake Humphrey

Jake Humphrey performed well throughout his GCSEs. However, when it came to his A-Levels, the story was different.

Since then, he has been remarkably open and vocal on social media, tweeting: “A-level students—remember results don't and won't define you. In 1999, I got an E, N, and U for myself. Things haven't turned out too bad...”

His successful broadcasting career came from being sacked from McDonald's.

Simon Cowell

Simon Cowell left school with just two O level—the equivalent of two GCSE—but then dropped out at 16. He began his career working in the mailroom at his father's company, EMI Music Publishing.

Now, Simon Cowell is known for the hit talent shows X-Factor and Britain Got Talent, which have been franchised worldwide.

Holly Willoughby

Former ITV presenter Holly Willoughby was privately educated and struggled with dyslexia. While she’s never disclosed her exact grades, she didn’t do well enough to study psychology at university.

However, as life unfolded, a new path pushed her towards a television career, landing her a role hosting the ITV Saturday morning kids' show ‘Ministry of Mayhem’. This led to her most notable show as host of ‘This Morning’.

Cheryl

Iconic girl group member and solo artist Cheryl went to school in Newcastle. However, the former Girls Aloud vocalist left without attaining a single GCSE.

Speaking to Huffington Post, Cheryl said: "For those who did well with their GCSEs or even managed to scrape by, their world is about to change. Maybe they're about to take up a place at college to study their chosen subjects, or maybe they have their dream job lined up. Either way, it's a time for celebration."

Ryan Gosling

After turning 17, Ryan Gosling decided to drop out of Lester B. Pearson High School and moved from Canada to LA to pursue his acting career. When Gosling turned 12, he tasted some fame in Hollywood when he joined Disney’s Mickey Mouse Club as a cast member. However, his big break came from The Notebook.

Adele

Adele is one of the biggest recording stars in the world - and she didn’t need a degree to get where she is.

While attending the prestigious BRIT school in London, she did not get any A-Levels. Instead, she has released four studio albums and won many awards worldwide including 16 Grammy’s.

Gemma Collins

Reality TV star Gemma Collins left school at 16. After leaving school with a ‘U’ in maths, Gemma wasn’t fazed.

Speaking to YOU magazine, she admitted: “I remember sitting in the exam room for my maths GCSE and thinking, ‘I’m going to be famous, I don’t need maths. What I really need is to go down Romford High Street and buy new shoes.”

Cameron Diaz

Cameron Diaz dropped out of secondary school at age 16 to pursue modelling full-time. She soon landed her first acting gig in The Mask and is now renowned for her roles in Shrek, There’s Something About Mary and Charlie’s Angels.