Kristen will be on 'The Tonight Show' with Jimmy Fallon on October 7

The The Tonight Show tapes in New York City and screens on the NBC network in the US. 

The taping of the show normally happens at approx. 5.00pm (ET).

11.35pm (ET), 10.35pm (CET).

Livestreams: 1 2 3 4  (Via) 

Look up your local time at the World Clock.

Source thank you to @KstewAngel for the heads up.