Equipping Items before helping

[Sliver]

If I ask someone to help, can he equip items before joining the combat?

[Clipper]

You can change your Items between being used and unused at any time while you are not in combat, so you can do this before finalising the agreement to help, yes.

[Sliver]

If those items aren't carried, can he still play them and equip before joining helping, or is it something you can only do during your own turn?

[MunchkinMan]

As is stated in the rules, you may play Items to the table on your turn or if you just received the cards. So, barring somehow having just received the Item cards, the potential helper could not play new Items to the table before joining the combat.