Kim Kardashian celebrates the Big 40 on October 21, 2020, and what better way to celebrate than with a trip down memory lane.

Forty years ago, a reality TV queen was born.

Four children, countless hair changes, thousands of OMG outfits, half a law qualification, a few trips to the White House, and a broken internet later, here's a nostalgic trip back through the annals of Kim Kardashian.

Fresh-faced with sister Kourtney, momager Kris and Caitlyn Jenner (then Bruce) in 2005, two years before the world was Keeping Up with their biz.

Another family shot, this time in skin-tight satin and bouncy hair with Kourtney and little sister Khloe (centre).

Noughties BFFs, Kim Kardashian was once Paris Hilton's wardrobe assistant, learning everything she knew from the Simple Life star. Hilton ran so Kardashian could walk...

And why were they attending Germany's Oktoberfest beer festival dressed in (sort of) traditional costume in 2006? Promoting a new sparkling wine, of course.

Of course, any noughties celebrity gang wasn't complete without Lindsay Lohan.

Like Hilton, Kardashian had a sex tape leaked, filmed with Ray J, her boyfriend at the time in 2007.

Kardashian also dated Nick Cannon - who went on to marry (and divorce) Mariah Carey.

In 2007, a reality empire was born. This one's from the Keeping Up With The Kardashians launch party, now with half-sisters Kylie and Kendall Jenner in tow.

Kimye would not become a thing until 2012, but the pair had known each other for a long time beforehand. Here they are pictured together at an event five years earlier.

With enough leopard print to be mistaken for a safari, Kim and the fam attended the Kardashian Kollection clothing line launch party in Hollywood in 2011.

Kim tied the knot with NBA player Kris Humphries (her second husband after music producer Damon Thomas in 2000), in 2011.

The marriage famously lasted 72 days.

Complicated, but in short, here's Kim and Kanye with Taylor Swift in happier times in 2015 - six years after the rapper interrupted the singer at the VMAs, a year before Kim leaked the infamous recording of Swift and West and branded her a snake.

Kim chose to cover up in florals for the Met Gala in 2013, when she was pregnant with her first child, North.

As well as her outfits, the star has also experimented with different hair looks over the years - including this bleached white transformation in 2015.

After getting together with Kanye, Kim underwent a bit of style evolution.

Out with the strappy tops, feathered hair, stretch dresses and knee-high boots, in with the full-on glamour and outfits showing off her famous figure.

First, we had the Beckhams in head-to-toe leather, then Britney and Justin braved double denim - here's Kimye giving us matching sequins in 2016.

As well as being a TV reality star, Kim has also launched a beauty business.

This picture was taken at her first KKW Beauty and Fragrance pop-up opening in LA in 2018.

As any woman knows, the two questions you ask your mates before a big night out are: what you wearing? And: are you taking a coat?

Needless to say, there was probably no chance of anyone else turning up in the same outfit as Kim Kardashian on this occasion.

Of all the many wow-factor outfits, this Thierry Mugler dress, covered in crystals resembling water droplets and worn to the Met Gala in 2019, has to be one of the most memorable.

Here's a better look, with added Kylie and Kendall Jenner.

Kim then slipped into something a little more casual.

In recent years, Kim has been using her platform to raise awareness for prison reform in the US and is also studying law. Here she is at the White House in 2019.

Kris Jenner and Kourtney, Khloe and Kim Kardashian at the People's Choice Awards in LA in 2019.

Full-on latex isn't the easiest look to pull off, but who cares about practicality when you're Kim Kardashian?

And never let it be said the star won't put comfort over style when it's parky.

Merry Khristmas! Here's Kimye and the kids - North, Saint, Chicago and Psalm - cosied up in some luxe loungewear on the family card for 2019.

The Kardashians announced this year that their 2021 series will be their last. Who will we Keep Up with now?

And finally, Kim Kardashian as we know and love her in 2020. Happy birthday, Kim!