That was likely the reaction most Glee fans had when they first heard that Neil Patrick Harris might guest star on this Fox hit.
He appears on How I Met Your Mother, they figured. No way this crossover would ever take place. But leave it to Ryan Murphy and his connections to make this dream casting a reality.
It takes place on next week's episode, aptly titled "Dream On." Get a look at Harris in the role of Will's former nemesis, Bryan Ryan, right now - and then check out the official promo for this monumental event below:
[video url="http://www.tvfanatic.com/videos/dream-on-promo/" title="Dream On Promo"] [/video]