Now this is a midnight memory.
The Bridesmaids star had the One Direction heartthrob's look down to a tee, from his signature haircut to his white T-shirt, black blazer, layered necklaces and point-toe black boots.
Presumably they traded jokes and talked about work, life (or, should we say, the story of her life) and other normal things, but...
We can't wait to find out if Wiig spoke in a British accent. (And is Harry going to show up later to confront his doppelgänger?! We know he was in London over the weekend, but that's just a short plane ride from New York...)
The pop superstar, who also helped Fallon kick off his new gig last night as one of the celebs who supposedly bet him a $100 that he wouldn't be host of The Tonight Show today, was spotted leaving her hotel in white loose trousers and a furry hooded pink coat.
Post-taping, Gaga was spotted out in NYC sporting oodles of sideboob in a pleated white apron dress (minus anything under it) and what looked like a Native American-inspired headress.
The Tonight Show Starring Jimmy Fallon, which is starting at midnight instead of its usual 11:35 p.m. this week due to NBC's Olympics coverage, got off to a huge start last night with 11.3 million viewers.
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