09/01/2015 AT 02:10 PM EDT

Well, that didn't take long.

It's been

less than month


Kermit the Frog


Miss Piggy


they were splitting

after four decades together, but it appears the plush amphibian has already moved on.

Kermit, who is still working with Miss Piggy on her late-night talk show

Up Late with Miss Piggy

– a situation that is being documented on the upcoming ABC series

The Muppets

– has been spotted around town numerous times with a head of marketing at ABC named Denise, a source tells PEOPLE exclusively.

"She's always stopping by the set of

Up Late

," the source says of Denise.

FIRST PHOTOS: Meet The Muppets' Kermit the Frog's New Girlfriend Denise| Couples, Muppets, People Picks, TV News, Kermit the Frog, Miss Piggy


Andrea McCallin / ABC

And it seems things are getting serious between the two.

"He calls her his girlfriend," adds the source.

RELATED VIDEO: Kerry Washington Stars in Adorable Muppets Promo

News of Kermit's new relationship comes just one day after an

Instagram post

from actor

Liam Hemsworth

sparked rumors that Miss Piggy

has also found a new love


"Spent Friday with the most beautiful girl in the world," the

Hunger Games

star posted along with a photo of himself with Miss Piggy. "Kermit, #SorryNotSorry."


Entertainment Weekly

reported, Hemsworth will guest star on

The Muppets

this fall.

The source confirms Denise will also appear on the docu-series, which premieres Sept. 22 at 8 p.m. ET on ABC.