A Gentile joining the IDF?

So I am talking to an old friend of mine the other day. He claims that a mutual aquaintence of ours hhas emigrated to Israel (from the US), and has joined the IDF.

The trick is, our mutual aquaintance is Catholic.

I said that he must have converted to Judaism to be able to join the IDF. (While talking to him, I googled the issue and found this to kinda-sorta back me up)

My friend says nope, our aquaintence has not converted, and is in the IDF.
Seeing as that we have some Israelis here, could we get this settled once and for all? Are non-Jewish men able to enlist in the IDF?

Yes, it is possible. Israel Defense Force opens doors to non-Jews, gradually