Today Headway Essex launch their annual fundraiser Hats 4 Headway. The charity provides support for people who have acquired a brain injury through injury or illness through their Day Centre in Colchester and through community support across Essex.
David Tennant has been a patron of Headway Essex since he visited the centre to research his role in Recovery, the BBC drama about a man who survives a brain injury following a road accident. The drama explored the debilitating effects of such an event not only on the individual but also on his family and friends.
It's the 30th Anniversary of Headway Essex this year so it would be wonderful if we could help them to a record-breaking fundraising year so they can carry on their crucial work. All they ask is a small donation. Fans in the UK only have to text HATS30 to 70070 and they'll have donated £3 - it's as simple as that.
If you're outside the UK or don't want to donate by mobile, click here to visit the Headway Essex Just Giving page. You can also help out by buying something from the range of David Tennant-related goodies in the webshop.
Don't forget, Headway Essex would love to see photos of you in your hats. Share them by tweeting @HeadwayEssex using the hashtag #Hats4Headway. And if you're feeling short of inspiration check out some of the glorious headgear that David has sported over the years.
David takes time out from rehearsals for Much Ado About Nothing to model for the 2011 Hats4Headway campaign. Yes, of course it's Catherine Tate's hat, David. If you say so...
David rocks a splendid flat cap and bowtie combo for an early TV appearance in The Mrs. Bradley Mysteries (2000)
Another cap, this time it's David's 'spy hat' from Spies Of Warsaw (2013). His character, a French colonel, also had a formal hat as part of his uniform but David elected to carry it rather than wear it because it looked ridiculous. On which point...
A stylish cat hat? Or an elevator for tiny kittens? David made an unusual entrance in this 2013 advert for Virgin Media
Top of your Christmas list? David demonstrated his expressive storytelling skills as a guest on the CBeebies Bedtime Story in 2009
Double trouble - David dressed sharp as one of separated twins, both called Antipholus, who cause confusion in Ephesus in Shakespeare's The Comedy Of Errors (RSC - 2000)
Just to prove that the Doctor will never, ever be able to walk past a fez without trying it on, no matter what face he has - The Day Of The Doctor (2013).
In 2008 David told the story of the unsung contributor to Einstein's Theory of Relativity in the BBC drama Einstein & Eddington
When the Tenth Doctor learned his end was near he ran off and had some fun. It was another 4 years before we found out what really happened with Elizabeth I. Still, try to make an Ood laugh... (The End Of Time, 2009)
The Play's The Thing - David was feted by many as the Hamlet of his generation and the 2008 Royal Shakespeare Company production was later filmed for release in 2009.
Saint or sinner? David played the Reverend Gibson, a slimy golddigger trying to climb socially through marriage in the BBC adaptation of Trollope's He Knew He Was Right (2004).
Only seen by a few - David models the Forester's costume he wore on stage for the understudy performance of Love's Labours Lost (2008)
It's NOT part of a mop bucket. It's a SPACE HAT! Why would you even question him? (2013)
Another Spies Of Warsaw spy hat. Mercier goes spying in some woods. He takes his spy hat off. He's immediately spotted by the Germans. Which just goes to show, you should never take off your spy hat. (2013)
David looks the part to hit the Top Gear circuit in this 2007 edition. Sadly, not only did he break the car but he later found out that Billie Piper had clocked a faster time.
If classic Doctor Who costumes appeared on set it was obvious who was going to want to try them on. Here David models an Old School Gallifreyan head dress for costume designer Louise Page (2007)
In the 2004 short film Traffic Warden David shows that parking attendants need love too. Especially if their hat gets run over.
He may look festive but in a few minutes Zombie Claus is going to be terrorising the Absolute Radio Breakfast Show crew in their 2013 panto.
We knew he couldn't bear to be parted from the hollow crown for long - David returns to the role of Richard II for the RSC early next year.