At a live appearance, Kamiya Hiroshi meows like a cat -- to the great delight of a largely female audience.
In the clip, egged on by the audience and by the seiyuus appearing with him, he does both the male and female character in a sketch, and delights the crowd by going "nyaan" (i.e., meow) like a cat:
Miyano Mamoru is on the far left, but I'm not certain who the other seiyuus are or when the appearance was. From nico.
Kamiya won the Seiyuu Award as top leading male of 2009 for his role of Araragi in Bakemonogatari, and is now playing both Rico in Arakawa - Under the Bridge and Izaya in Durarara.