Actor Daniel von Bargen died Sunday at the age of 64 after reportedly battling a longtime illness. As news of his death becomes more widely reported, condolences have been pouring in for the late actor from colleagues and friends. He was best known for his roles on both “Seinfeld” and “Malcolm in the Middle.”

According to People magazine, both Jerry Seinfeld and Jason Alexander spoke highly of von Bargen, whom the two briefly worked alongside while filming “Seinfeld.”

“That guy was so great! I just saw that myself on the news,” Seinfeld told People during the inaugural Los Angeles Fatherhood Lunch To Benefit Baby Buggy. “You know, whenever that happens, I think of their funny things that they did.”

Alexander, who worked more closely with Von Bargen on the show, also commented on the actor's death, saying, “He did a lovely job on the show and seemed like just a sweetheart of a man.”

“It's sad," he added. "It's just sad.”

Von Bargen was known best for playing George Costanza's boss, Mr. Kruger, on “Seinfeld.” He later landed another notable role as Commandant Edwin Spangler on “Malcolm in the Middle.” Though his roles were not always the lead, Von Bargen appeared in numerous well-known films including “Silence of the Lambs,” and “O Brother, Where Art Thou?” He also had a lengthy career both on and off Broadway.

Seinfeld and Alexander weren't the only ones with kind words and fond memories of the 64-year-old. Von Bargen's voiceover agents were “deeply saddened” by his passing, according to a statement released to People on Wednesday.

“We are learning of this event at the same time as the rest of the industry and are deeply saddened to hear of Daniel's loss,” they said.

The actor is said to have struggled with diabetes for many years, which hindered his ability to work and caused him to spiral into a deep depression, a number of outlets reported. In 2012 the Ohio native attempted suicide, shooting himself in the temple.

“For the past five years, he has been grappling with health issues that precluded his active pursuit of work,” his former agents revealed to People.

“We remember him fondly for his easy-going professionalism and dry wit, both of which stood in stark contrast to the driven and near-maniacal roles he often performed with such energy and intensity,” they added. “He was a joy to work with and we have missed that association since his semi-retirement to Cincinnati.”