Why on earth are you doing show like I'm a Celebrity… Get Me Out of Here?
"Why am I doing a show like this? I'm doing this to lose some weight, obviously. I think that's the inevitable goal. It's something that I embrace because I don't have the will power to lose weight on my own. I think it's very kind of ITV to sponsor my weight loss."
Is there any particular reason why you want to lose weight?
"I'm a fat b**tard! That's the only reason. I'm 20 stone at the moment and I'd love to lose 5 stone in the jungle. I'm not a great drinker, so it's all down to food. Bangers and mash, beans on toast… I'm British you know."
You might be disappointed in the Australian jungle when you're presented with a kangaroo penis to eat on the show…
"I know. I've heard about the jungle menu. As long as it's not attached to the kangaroo I don't mind!"
Which type of Bushtucker Trial would you most like to tackle in the jungle?
"I guess I like the trials that are a broader challenge rather than just sitting and eating odd foods. I like challenges that test your ingenuity. I don't think I have a particular favourite, though."
Are you prepared to tell lots of showbiz tales to your fellow campers in order to ease the boredom and keep everyone entertained?
"Why should I cope with my boredom by boring the pants off the others? I suspect that we'll find plenty to chat about that doesn't bore the pants off each other. I hope so anyway."
Are you worried about getting caught in your underwear with the cameras rolling 24 hours a day?
"I think the viewers should be more worried about that than me. If people want to look at what I've got, they are very welcome. I don't think they are going to reap in there with any enjoyment. They're going to hide their faces and say, 'No, please turn it off.'"
What message do you have for your legion of loyal Doctor Who fans while you are in the jungle?
"Bless the Doctor Who fans. I was in the show from 1983 to 1986… Blimey, it's been 30 years since I did the programme! Well, they have all been faithfully loyal. There have been a lot of rumours flying around about me going into the jungle and I was trying to avoid any contact with people after I signed up - but they have already been very supportive. I know that my legion of wonderful people will vote for me. Bless them."
Do you still watch Doctor Who?
"Do I watch Doctor Who? Of course I do. And I absolutely love Matt Smith. When I heard another young [guy] was going to be playing the Doctor, I thought, 'Hmmm… Not another young one. Why don't they have an old geezer again, like me?' Suddenly, along comes this 29 or 28-year-old guy playing a 300-year-old Doctor - and he's brilliant. He encompasses all of the previous doctors and adds a bit himself."
There are always rumours circulating about a big-screen Doctor Who movie. Have you been approached to appear?
"I haven't been approached to do a Doctor Who movie. I think they would be scraping the bottom of the barrel if they asked me to do it. All you have to do is hold up a picture of what I look right now and what I look like then and you'd know why."
What about a cameo role?
"A what? What's a cameo role, darling? Does that mean a small part? Urgh! I suppose I might. I don't know. I find it a bad idea to say what would you do if you were asked, which is why I'm going to say no, I probably wouldn't appear in any movie. They would have to persuade me."
Next year is the 50th anniversary and there's lots of speculation that there will be a multi-doctor special. Have you been asked?
"No. As far I know, neither of any of my erstwhile colleagues have been asked either."
What would it mean to you if you were crowned king of the jungle?
"If I were crowned king of the jungle, it would mean that I would have lost a lot of weight! Obviously, the king of the jungle is the one who lasts until the very end, so that means I'll have missed even more food than most."
Do you think you've got a chance of winning the show?
"There are probably going to be a lot of very gorgeous young women and very handsome young men in the jungle. The voting demographic will probably see one of them as king or queen of the jungle."
What would it mean to you if you did win the jungle crown?
"If I were crowned king, I would be chuffed beyond reason. I haven't won an awful lot in my life, so it would mean quite a lot to win something now. I'm going into the jungle with the intention of winning. I'm certainly not going to go for the easy option of being fairly boring and getting voted out early so that I can swim around in a luxury hotel while the others battle it out."
Why should the British public vote for you?
"There's no reason at all why they should, but I'm hoping that with what they see and what they are shown, they might think, 'He's alright; I'll vote for him'. I'd vote for me because I think us oldies, we need support."
I'm a Celebrity...Get Me Out of Here! stars tonight (November 11) at 9pm on ITV1.
Photo gallery - I'm a Celeb 2012 lineup: