There won't be much laughter tonight.

"It is with great sadness that the staff and crew of 'Jimmy Kimmel Live!' mourn the loss of 'Uncle Frank' Potenza," ABC said in a statement.

"Thank you for your kind words about a very kind man -- my Uncle Frank -- who passed away this morning," the late-night host tweeted.

Potenza, 77, was a security guard for the show, and made appearances numerous appearances during his nine years on the program, including in segments called "Guillermo's Hollywood Round-Up" and "Uncle Frank and Aunt Chippy's Adventures." Prior to working on his nephew's late-night program, Potenza was a New York City police officer, and security guard at Caesar's Palace in Las Vegas.

"He was beloved by his co-workers and considered an uncle to all," the network said. "His kindness and humor will be missed by everyone he touched."