Well, we might not ever get to meet Ted's kid's mother on How I Met Your Mother, but at least we'll get to meet Barney's dad. And surprise, surprise it's John Lithgow! Wait, we already knew that. Dang, so that's not a surprise anymore. Ah, well then this seriously confirms that he is indeed the father. I'm just glad we didn't have to get Maury in here to settle this. Even though that would be hilarious to see with Neil Patrick Harris. Alas, this one gets shuffled off into the dream folder.
Anyway, you can see Lithgow on HIMYM starting March 21st.
Source: TV Line