THOUSANDS of men and women all over the world will be getting hairy this November for good causes.
That's because Movember starts on the first of the month. Here's our guide to what it's all about, which charities it supports and how you can get involved.
What is Movember?
It started in 2003 with a group of 30 lads in Melbourne who decided to grow moustaches for a bit of a giggle.
The next year 450 men took part and they raised around £25,000 for prostate cancer research.
The trend quickly grew into a global phenomenon and is now a major annual event.
Now around five million people - dubbed Mo Bros and Mo Sistas - take part in at least 21 countries.
Every year 10,000 men die of prostate cancer - one an hour - and suicide is the biggest cause of death in men under 50.
The charity says men are facing a health crisis that isn't talked about, and by 2030 aims to cut the number of men dying prematurely by a quarter.
How do I get involved with Movember?
The first thing you need to do is register.
Once signed up, you can decide whether you’re working alone, or whether you want to team up or join another "pack".
There are also events to join such as fun runs, quizzes and dodgeball tournaments.
You can even host your own party for you and your mates to compare facial growth.
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What are the rules for Movember?
Every participant starts with a clean shave on October 31 - with a "before" photo to prove it - so you best get cracking!
Mo Bros then spend the next 30 days growing and grooming their upper lip hair. You get extra kudos for unusual styles or recreating the look of a famous tache wearer.
If you're being strict, no beards are allowed. That means you cannot join your moustache to sideburns, or join chin hair to handlebars.
However, the organisers want as many people as possible to get involved, so people who already have a beard are encouraged to sacrifice it to make way for a Mo at the start of the month.
On November 30, take a photo of your effort and share it with friends, colleagues and anyone you begged to sponsor you.
One of the great things about Movember is the sense of community.
Even if you don’t know anyone who is doing it, you can join in the events and parties and connect with tache growers across the world through the Movember app.
Girls can get involved too by donning false moustaches at the parties and fun runs.