We thought that Henry's gift would be a surprise for him, but it turned out to be a surprise for us. Henry found his gift in the closet long before Christmas. We didn't make a big deal of it, just shut the door and moved on. I wrapped it up a week or two ago and Henry seemed to forget about it once he couldn't see it.
Christmas morning we brought it out for him to open. He didn't seem overly excited, but we figured this was due to the abundance of gifts he had already opened from our extended family.
Maybe next year we'll just wrap up the toys he already has and give those to him again!