Tina Fey Tries Her Sofia Vergara, Robert De Niro Impressions on Jimmy Fallon (Video)

Tina Fey swapped celebrity impressions with Jimmy Fallon on “The Tonight Show” Monday night, and the results were hilariously awkward.

“It’s tricky because I stink at impressions and you’re very good at impressions,” Fey said at the outset, after both she and bandleader Questlove attempted to imitate Robert De Niro with a squinty eye and downturned mouth.

“Why did we write this game up? This is not fun at all,” Fallon told Fey, who was appearing to promote her new big-screen comedy, “Sisters,” co-starring fellow “SNL” alum Amy Poehler.

The game of “First Impressions” began with Fey trying to sound like Jack Nicholson — which Fallon guessed was either Matthew McConaughey or Nicholson.

Then Fallon tried out Barbara Walters — “I once saw a walrus resting on a rock” — which Fey correctly guessed despite the host’s admitted inexperience trying the veteran newswoman’s voice.

“You’ve done Barbara Walters a million times,” Fey ribbed.

In the next round, Fey channeled Sofia Vergara, complete with a hair flip and an attempt to fluff up her breasts to appear like the buxom “Modern Family” star.

Fallon then tried to imitate Morgan Freeman, prompting Fey to guess either Freeman or “Sling Blade” — or, more precisely, Adam Sandler‘s impression of Billy Bob Thornton‘s simpleton.

For the final round, Fey seemed to ingest helium to proclaim, “There’s a monster on the stairs. ” And Fallon correctly surmised that she was voicing “Sesame Street” regular Elmo.

“The Tonight Show” airs at 11:35 p.m. on NBC.