The hit ITV show I'm A Celebrity...Get Me Out Of Here! kicks off on Sunday.
The highlight of every series is the banter between the two presenters Declan Donnelly and Ant McPartlin.
ITV have issued publicity pictures for the new series in which Dec's hair is looking darker and fuller.
You can see the difference in his hair in pictures below - the recent publicity picture is on the right.
It begs the question: has he had a hair transplant?
Dec has been struggling with hair loss for a number of years - with noticeably thinning hair right across his scalp.
He is 44 - by which time around half of men are experiencing male pattern baldness.
Dec has denied through friends ever having a hair transplant.
However, his hair is looking noticeably fuller - and darker - in the recent publicity pictures.
So what is going on?
There are three likely explanations.
1 Hair loss medication - it is likely that Dec has been taking a clinically proven hair loss medication such as Finasteride, also known as Propecia. This will not help the star to grow any new hair but it should stop or slow down any further natural hair loss.
Crown Clinic's consultant hair transplant Asim Shahmalak sometimes recommends the use of Finasteride, particuarly to patients in the early stages of male pattern baldness who perhaps are not ready for a full hair transplant.
Sometimes Dr Shahmalak combines a full hair transplant - either a FUE (follicular unit extraction) procedure or the more traditional method of FUT (follicular unit transplantation) - with a prescription for Finasteride.
A hair transplant is the only long-term solution to hair loss but this hair loss is a continual process. So even after you have had a procedure, you could still end up losing more of your natural hair, though the transplanted hair will be permanent. That is why a twin approach - hair transplant AND Finasteride - works for some patients.
The same friends of Dec who denied that he has had a hair transplant have indicated that he DOES use hair loss medication to combat his hair loss.
The DJ Chris Evans is another star who has indicated recently that he uses hair loss medication. Chris says he has hair loss 'drops- - almost certainly Minoxidil, another clinically proven hair loss medication prescribed by Dr Shahmalak.
2 Hair thickener - lots of stars use thickener to give the impression that their hair is thicker than it really is. This can be a useful treatment if you just need a little pick-me-up and want to temporarily disguise your baldness.
It would make sense for Dec to use thickener for a big photoshot for I'm A Celebrity so that he will look great in all the pictures in newspapers, magazine and online.
Hair transplant patient Wayne Rooney used to use thickener on his hair before big England games so he would look good on TV.
3 Hair dye - Dec is almost certainly dying his natural light brown hair a slightly darker shade of brown. Darker hair doesn't show off male pattern baldness as clearly as lighter hair.
So this is another disguise that Dec is using to cover up his baldness.
Dec could get a permanent solution to his male pattern baldness with a hair transplant. Around 80% of the patients at Crown Clinic - including most of Dr Shahmalak's celebrity clients - opt for an FUE transplant - where the donor hair is removed one-by-one, thereby minimising the scarring.
Famous Crown Clinic FUE hair transplant patients include Jack P Shepherd from Coronation Street, Homes Under The Hammer presenter Martin Roberts, model Calum Best and the former Liverpool and Man City footballer Didi Hamann.
Some Crown Clinic patients still prefer the FUT hair transplant, where a strip of skin is removed to obtain the donor hair. This method is slightly cheaper than FUE because it is not so labour intensive but it is not suitable for patients who wear their hair shaved or short at the back and sides due to the scarring.
The TV doctor Christian Jessen had two FUT transplants with Dr Shahmalak at Crown Clinic.