JG yeasayer Yeasayer performs on late night February 18, 2010September 6, 2016 admin Yeasayer stopped by the studios of Late Night With Jimmy Fallon last Wednesday, Feb. 10 and performed their single “Ambling Alp.” Check out the episode here and fast-forward to Chapter 6 for Yeasayer’s performance. The performance will be available to view on NBC’s site until Saturday, March 6.