How do I heat my gammon up?

[Sausagefingers9]

Slow cooked a gammon last night and put it in the fridge overnight. How can I heat it for lunch? Can I just whack it in the hostess trolley or should I oven it first?
Help!

Following as would also like to know the best way to do this? Heat up whole and then slice or slice and then heat up?

I normally slice and pop in a roasting Tim with some wine or warm water and cover with foil till warm.
It keeps it moist

I scan read that as how do I heat my grandma up..... backing out the thread now

Slice and then heat.

Make him put another jumper on