Paying a visit to Conan‘s couch on Monday, Neil Patrick Harris revealed that the TBS late-night host had generously outbid all comers to win a charity auction and thus land a walk-on role on CBS’ How I Met Your Mother this season.

Upon learning of O’Brien‘s winning largesse, Harris said he tried to coax him into really suiting up by tackling a speaking part. CoCo, however, has his own plans for the cameo, which he reveals in this clip (on or around the 5:30 mark):

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A CBS rep did not immediately respond to our request for details — if any are even yet available — on O’Brien’s visit to MacLaren’s.