The one day of the year is back when it's not unusual to see celebrities on TV, children at school, and even passers-by in the streets, all donning a spherical red accessory on ther face.

That's right - today, March 15,  is Red Nose Day in the UK - the annual charity event will be broadcasting live tonight starting at 7pm across BBC One, BBC Two, and BBC iPlayer. 

Filled with live performances and one-off comedy specials, a host of famous faces are set to team up in a bid to raise money for those struggling in Britain and beyond.

But, have you ever wondered how and when the unique annual tradition began?

Here, FEMAIL explains why we wear a Red Nose to raise money for charity and what the meaning behind it is... 

WHY DO WE WEAR A RED NOSE ON RED NOSE DAY? 

The reason we sport the squishy red accessories is actually all because of the founders of Comic Relief - Sir Lenny Henry and Richard Curtis.

When they were in the process of creating Comic Relief, they were on the hunt for a bold and fun charity symbol that everyone could wear.

Someone in the meeting joked: 'What about a Red Nose?' and the rest is history.

The whole message of Comic Relief is raising money through comedy, so the organisers had to pick something that related to that and would attract public attention to raise the most money for charity.

So, what better for a comedy event than a stand-out symbol that reminds us all of clowns? 

WHAT IS THE MEANING BEHIND RED NOSE DAY AND WHEN DID IT BEGIN? 

Comic Relief started as a charity in 1985 with a goal to raise as much money as possible for lives in Africa and the UK after the success of Live Aid that same year.

Fast forward three years and the distinctive Red Nose was born in 1988.

The first Red Nose Day was shown on the BBC in front of over 30 million viewers raising £15 million for the charity, with over 150 celebrities and comedians getting together to take part.

However, the first ever Red Nose itself was a simple concept in comparison to the designs of today.

It was a plain plastic Red Nose for people to buy to raise money for the charity and to wear on the day. 

The designs have become more unique throughout the years, from a Nose with arms in 1991, to furry Noses in 1997 and the first with a silly face in 2001. 

WHAT ARE THIS YEARS RED NOSES? 

This year's Red Noses consist of four brand new fun characters to collect – Gigglesworth, McChortles, Smirklethorpe and Lol E Pops.

There is also a 1 in 166 chance to get your hands on a limited edition Rare ‘Gold’ Nose - the Golden Hooter.

Plated in 24-carat gold leaf, only a limited amount of people will get their hands on the rarities. 

The Noses are made from plant-based materials meaning they can be recycled at home and are suitable for children aged 3 and above. 

This year is also one to remember, as Sir Lenny Henry will host the fundraising show for the last time this year, after 39 years of presenting the comedy telethon.

A star-studded cast will be co-presenting the charity night, including Joel Dommett, Davina McCall and Paddy McGuiness.

Romesh Ranganathan, David Tennant, Maya Jama and Rosie Ramsey will also be taking to the stage to be a helping hand.

The night is also set to be packed full of fun with hysterical sketches from Lenny himself and an all-star cast bringing to life The Traitors: The Movie.

Meanwhile, Radio 1 DJ Mollie King has traded in her microphone in exchange for a bike as she makes an epic 500km journey cycling journey across the UK to raise money for Comic Relief.

The former The Saturdays star, 36, is taking part in the Pedal Power challenge which sees her trek across England in the space of only five days.

After off on Monday from London, the singer hopes to arrive in her late father Stephen's hometown of Hull on Red Nose Day (today).