Ben Stiller Admits He's Nervous Before Testifying on Syrian Refugees

Ben Stiller is on Capitol Hill with a stomach full of butterflies ... admitting to us he's nervous to go before lawmakers and testify on the humanitarian crisis in Syria.

We got Ben before he went in front of the Senate Foreign Relations Committee Wednesday to try to convince legislators to help out Syrian refugees ... and the actor told us he couldn't help but feel nervous about his big moment.

Ben's the goodwill ambassador for the United Nations High Commission for Refugees, and he's pleading with countries who host refugees to help ensure long-term support for displaced people.

This is his first time testifying on Capitol Hill ... so you can understand why Ben's anxious about pleading his case in front of a bunch of Senators.

Well, he has had some experience testifying, but we're guessing his hilarious 'SNL' skit -- playing Michael Cohen testifying on the Hill -- doesn't really compare to the real deal.

Let's just hope he doesn't slip into Cohen mode. Ben did tell us one of his classic roles could come in handy, though, during this testimony.