People can’t believe age difference between Rachel McAdams and actor who played her mum in Mean Girls

Seen as though most of us still quote the film's iconic lines on a daily basis, religiously wear pink on Wednesdays and have made 'October 3rd' something of a national holiday, it's hard to believe Mean Girls has just celebrated its 20th anniversary.

The timeless teen comedy still has film fans in a chokehold two decades after its release in April 2004, so it's no surprise that the emergence of behind-the-scenes secrets still cause pandemonium.

For starts, the flick written by Tina Fey was apparently originally supposed to be called 'Homeschooled' in reference to Cady Heron's transition from at-home education to high school - which really doesn't have a ring to it.

Despite being released 20 years ago, Mean Girls is still the Queen Bee of teen comedy movies (Paramount)

Ashley Tisdale and Blake Lively also both auditioned for roles in the film too, while teen heartthrob Aaron Samuels, played by Jonathan Bennett, was scouted for the gig while working as a model at Abercrombie & Fitch.

And that isn't enough for you, wait until you find out that the leading lady in Mean Girls, Lindsay Lohan, was going to star as queen bee Regina George at one point - but ultimately, Rachel McAdams bagged the part.

But despite all these interesting bits of Mean Girls trivia, it's the age difference between McAdams and the actress who played her mum in the movie which has really got people talking.

Amy Poehler played the pink Juicy tracksuit-wearing Mrs George, who is best known for offering out 'hump day' treats and having fake boobs that are 'hard as rocks'.

And boy, did she do the job well:

The self proclaimed 'cool mom' might seem like she's been around the block a few times in Mean Girls, but in real life, she was a lot closer in maturity to her on-screen daughter than you might think.

Red Eye star McAdams, who is now 45, had just 25-years-old when she starred as the teenage terror Regina.

But Poehler didn't have that many years on her, despite playing her mother in the film.

The comedian, 52, is only seven years older than McAdams and was just 32 when she starred as the iconic character.

Even Kris Jenner has paid homage to Poehler's character in Ariana Grande's 'Thank U, Next' music video, so it's safe to say Mrs George a cinematic legend.

And people can't believe Poehler pulled off the role of a maturer woman so well and took to social media to share their thoughts after finding out about the small age gap.

Amy Poehler was only a few years older than her on-screen daughter (Paramount)

One said: "I just learnt I'm the same age Amy Poehler was when she played Rachel McAdams mum in Mean Girls (32), and that has COMPLETELY RUINED MY DAY."

Another said: "I'm watching Mean Girls because I was curious if it aged well and it's really funny that Amy Poehler plays Rachel McAdams' mom despite being only 7 years older. But it works."

A third added: "Every now and then I think about how Amy Poehler was 33 in Mean Girls playing the mom of Rachel McAdams, who was 26. That’s so crazy lol."

While a fourth wrote: "Mental how Rachel McAdams was 26 when she was in Mean Girls, and Amy Poehler (playing her mum) was only 33."