David Tennant and Billie Piper took part in yet another laugh-packed joint panel on Thursday when they kicked off their marathon weekend of convention appearances. The event took part one Day 1 of Emerald City Comic Con at the Washington State Convention Center and was hosted by Clare Kramer. 

Here are a few highlights from David's responses to questions:

On being cast in Doctor Who
"It was all a bit weird because I knew the show was coming back, a show I'd watched since I was tiny, but it hadn't been on TV yet so I didn't really know what I was being asked to join in on. And it felt like a weird idea to bring Doctor Who back, it didn't feel like the sort of show that the word was ready for back then. Doctor Who felt like TV history. Not knowing if the show was going to work or not, it felt like quite a big gamble. It might have been a big flop!"

On his first Doctor
"My first Doctor was Tom Baker, he's the first one I remember...I was still watching when a man called Peter Davison took over. And now I see him for Sunday lunch! So it's all quite strange and quite unlikely, but very lovely."

David added that on his first day of filming Doctor Who he received a note:
"It said something like 'If you have half as good a time as I did you're in for the ride of your life.' That was from Tom Baker"

On returning for the Big Finish audio adventures
"It was like putting on an old coat"
On learning that Billie would be doing more: "I might end up..."

On John Barrowman
"John is an absolute force of nature, he's a wonderful, extra-ordinary human being."

On working with Catherine Tate
"It's quite a lot of fun. It's great. Catherine's a hoot, very easy to work with."

On favourite Doctor Who episodes
"I had a fun time doing them all. Then when everyone came back for The Stolen Earth and Journey's End, that was enormous fun as well."
"My favourites episode that I'm not in...I like the one [Billie] and Chris did - Father's Day, with Shaun Dingwall"

On the future of Doctor Who
"I'm very excited to see Jodie Whittaker start and see what different direction that will take everything. I don't wish for anything other than it keeps being a fun, crazy show that I've loved since when I was a kid.

"[Jodie's] great, she's very funny, very lovely, she's a very good actress, the three qualities that are essential to play the Doctor. She's got them all in spades so I think people are in for a treat. "

On filming Hamlet for TV
"What's great is I knew all the lines already! I'd never done anything like that where it existed in another form and we were putting it on screen...what was great was being able to come to something where you'd basically rehearsed it for a year because we'd done it so many times. So, having to do it in a different medium was kind of challenging but kind of freeing as well. 

"I'm very glad I got a chance to do it. One of the things about theatre is that it's so intense when you're in it and then it disappears again, it dissipates into the ether forever, so it's nice that we got to have a record of it."

On what he looks for in roles
"You just read something and it's a bit of writing that appeals to you. That can be because it makes you laugh or because it's something you've never done before. For me it's when you read a script...and you want to be part of telling that story. Sometimes because it moves you, sometimes because it's the type of story that's never been heard before. There's no single answer to that. Sometimes it's the chance to work with specific people."

On moving between adult roles and children's, specifically Scrooge McDuck
"It's all the same stuff. It's all about finding the truth of the moment. The truth of being a 900 year old duck who water skies and does whatever else he does!

"It's been a great honour to take on the mantle of Scrooge McDuck, and it's something that keeps going. We're doing more and more. [Animation work] is much quicker and you don't have to put funny clothes on...although I do dress as a duck!"

Advice for aspiring actors
"I'm very bad at giving advice. If you can do something else you probably should. Only because there's far too many of us all after the same jobs. But it's a great life!"

On staying in character away from the set
"It's hard because unless you very consciously go home deep in character, which is quite a self-conscious thing to do, I would suggest...It may be true a sort of mindset can affect you when you're doing something, but it's maybe something that you're not even aware of yourself. That's for people around you to maybe comment on after the event, but no, I don't go home doing a voice. Doing the school run as the Doctor would be dangerous! 'Quick! Run!'". 

What book changed his life?
"When I first read Sallinger's stuff it was quite life changing. I read it all at once in my late teens and early 20s and it felt like it was just written for me."

On being told he has influenced people to go into acting
"[That's] humbling, I suppose. It's not something one is aware of or sets out to do necessarily. But it's lovely...I feel a bit shy."

David Tennant will take part in another panel with Billie Piper tomorrow morning at Wizard World Cleveland, starting at 11.45 ET.