Round-up and video of all of David Tennant's 45 minute panel at Wizard World Columbus today.
As well as talking about Jodie Whittaker becoming the Thirteenth Doctor, David announced that Mad To Be Normal will be released in the US. He added "We've only just heard but we're not sure at the moment how it will be released." Updated 5/8

The first photo of David Tennant at his photo session at Wizard World Columbus today has been posted to Twitter. Updated 5/8

A closer version of that photo of David Tennant signing autographs at Wizard World Columbus has been posted to Twitter. Updated 5/8

Wizard World posted to Twitter the first photo of David Tennant today at their fan convention (signing autographs) with the caption 'Someone is having a really busy morning.' Updated 5/8

David Tennant is a guest at Wizard World Columbus fan convention today. Updated 5/8

Catherine Tate to also appear at Wizard World Columbus fan convention.
The website does not make it clear yet whether there will be photo ops for David with Catherine but currently they are not on sale so it looks unlikely. The website also lists solo panels so it seems there will not be a joint Question And Answer panel.
John Barrowman is also attending this fan convention. Updated 20/7

John Barrowman to join David Tennant at Wizard World Columbus fan convention in August.
At Wizard World Columbus David Tennant will only appear on Saturday 5th August but John Barrowman will also attend on Sunday 6th August. Updated 10/6

Two more US fan conventions have been added for David Tennant.
They are Wizard World Columbus on Saturday 5th August and Wizard World Chicago on Saturday 26th and Sunday 27th August. Updated 1/6