Upvote:3
Yes. You do not want to lie. As @phoog said and as I would like to add on, you should mention everything. Lying can have serious consequences and you or your friend might accidentally let something slip. It could be minor, "Italy is such a nice place", or major "Have you visited [landmark]? I went there yesterday."
As @Blackbird57 said, lying may also negatively affect future visa applications.