Can a magus use spellstrike on an attack of opportunity?

Question

A magus casts Shocking Grasp, uses the arcane pool (for +1) and walks into battle. The baddie runs past the Magus, and the Magus gets an attack of opportunity, can he use Spellstrike and deliver the Shocking Grasp?

The rules seem silent on this--but my gut tells me that they would be able to discharge the spell through an AoO because it is a melee attack (if they hit). I just want to see if there are any rules or rulings on the subject.

Answer 1

Yes, a magus can use spellstrike with an attack of opportunity.

An FAQ from Paizo designer Sean Reynolds specifically states that once a magus with Spellstrike has cast a touch spell they can continue to hold the charge and deliver the spell with a melee attack later. Once their hand or weapon touches something the spell is discharged, but until that time they can deliver the spell with a melee touch attack or a melee attack, which would include an attack of opportunity.