That’s Brian Dobson, who voiced Skeletor in the 2002 CN Masters of the Universe series, and the great Alan Oppenheimer, who voiced Skeletor (and about half of the rest of the characters) in the original 80s series. They’re playing with figures of the characters they helped make famous (infamous?).
The best (only good?) thing to come out of the constant gritty rebooting of everything under the sun is that every now and again, we get to see old and new(er) actors that played the same part hanging out.