Little-known fact about Jason Sudeikis: Whenever Will Forte does a talk-show appearance, Sudeikis is there, stowing away somewhere on set. It’s not a creepy thing; you just never know when the opportunity for a good REO Speedwagon duet is going to arise, and, what, is Sudeikis going to not be there when it happens? Get your lighters out and your phone’s flashlight app going, because Forte and Sudeikis sang a duet of “Can’t Fight This Feeling” on Thursday’s Tonight Show. Indeed, the feeling was so strong that the duo seemingly blew right past a commercial break. Jimmy Fallon ships it.