Has to be Diamonds. King of Hearts is usually a suicide king with a knife sticking in the side of his head facing forward. As far as odds go preflop I don't think the suit of the red king really makes a difference because there is no way they share that suit since the jacks are both black.
I think the KK's are about a 79/21 favorite so the odds would be whatever that split happening 3 consecutive times would be. For that I don't know how to calculate it.
The answer might be .21 to the 3rd power. If that's the case it's .0926%, so just under 1% but I'm no probability wiz and I could be way off.