Zac Efron and Seth Rogen are hysterical when acting like teenage girls!

The acting duo, who co-star in the comedy flick 'Neighbors', dressed in drag on Tuesday night (May 6th) as part of the 'The Tonight Show's' recurring "Ew!" segment, and were joined by the host, Jimmy Fallon.

Zac Efron
Efron dressed as a teenage girl called Brittany Anderson

TeenNick, the name of the TV show, is emceed by the very pretty Sara Wallace (Fallon), and she invited her guest star, and "bestie," Allison Donnelly (Rogen) onto the set to talk about what she's been up to.

Fallon wore a blonde wig with a bow, braces, and a purple dress with a heart-shaped necklace, whereas Rogen donned an auburn wig with a braid, a floral sundress, and a necklace reading "MAYBE."

Seth Rogen
Seth Rogen wore a auburn wig for the skit

"My mom gave me her credit card so I stopped by Starbucks on the way here," Allison said. "Ew!" Sara replied. "What did you get?"

"A venti soy cinnamon dolce cream Frappuccino!" Allison said, but did she also get the whipped cream? "Ew!" she told Sara. "Of course!"

The two teen girls' other BFF then entered, and it just so happened to be Zac Efron in the character of Brittany Anderson, so what has she been doing lately?

"I'm actually super excited right now because I just got this new phone and it has an amazing camera," she told her pals. "It's got, I think, like, eight megapixels-so it's like perfect for selfies! I've been taking them all day!"

Watch the "Ew" segment below

After taking several snapshots, the trio began to dance to Lil John's song 'Turn Down For What', before being disturbed by Sara's "lame" stepfather.

The skit ends on a hilarious note by mocking Rogen's good friend, and frequent collaborator, James Franco. They all branded him an "Ew" after they each receive a text off the actor.