There haven't been too many people who have voiced the character of Megatron over the years, and only a few of those have been a guest at Transformers conventions.
This year, the 2001 Robots In Disguise Megatron voice actor Daniel Riordan will be a guest at the UK fan convention TFNation, in August.
A treat for the UK fans, and anyone keen enough to travel there later this year.