At least in TechDays Belgium 2013 .
Because, there is a Bart De Smet Unplugged session, which usually for stars, right ?
The other two sessions are also interesting: Behind the scenes of (as many) C# language features and Introducing TypeScript, apparently Bart knows EVERYTHING, curious what he is working on now, according to LinkedIn:
October 2012 – Present (6 months) Bellevue, WA
Yet unannounced projects.
March 2012 – September 2012 (7 months)Redmond, WA
Working on Reactive Extensions (Rx) v2 and various LINQ-related projects.