The CBS Late Late Show host made a surprise cameo last night as British Prime Minister Boris Johnson in Saturday Night Live's cold open parodying Canada Prime Minister Justin Trudeau mocking President Trump with Johnson and French President Emmanuel Macron at last week's NATO Summit in London. Fallon returned to SNL as Trudeau, while Rudd played Macron. This is the second time in a week that Corden has appeared on a rival network's late-night show. Corden stopped by Jimmy Kimmel Live! last Monday. Corden's cameo comes amid a break from The Late Late Show Show to film the Ryan Murphy movie Prom. "Well... That was a dream come true. Thank you @nbcsnl for having me. I loved every second," Corden tweeted.