Mark Harmon made his television debut in a Kellogg’s commercial with his father

Mark Harmon originally didn’t particularly like his acting debut.

The 73-year-old actor recently joined Kelly Ripa and Mark Consuelos Live with Kelly and Mark in Palm Springs on Wednesday, November 13th. During their conversation, he told the daytime talk show hosts that his first role was actually alongside his father, football and broadcasting icon Tom Harmon.

The NCIS star explained that his father was a Kellogg’s spokesman and he was asked to appear with him in a commercial for one of his products, specifically Product 19 cereal.

“I was in a commercial in the backyard eating cereal, which never happened,” he joked with Ripa, 54, and Consuelos, 53. Harmon confirmed that he had just started high school at the time.

“So I imagine my own children. Would that be embarrassing for you?” Ripa began, before the Emmy nominee immediately chimed in and confirmed that it was “humiliating.”

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Even though people didn’t recognize him, the commercial changed [his] “I think I saw something, that crew, those people around me, that I understood.”

Consuelos chimed in and said, “Plus the paycheck is good. Were you paid for this commercial?”

“My father did it. I think,” Harmon said with a laugh. “I think there are laws against it now,” Consuelos added, and Harmon replied, “Not then!”

Since that first commercial, Harmon has starred in several projects, from Crazy Friday To Illegal work And St. Elsewherebut he stuck to his NCIS character, Special Agent Leroy Jethro Gibbs, for nearly two decades.

Harmon starred in the series Military Police for 19 seasons until his departure in 2021. Since its premiere in 2003, the series has spawned five spin-offs: NCIS: Los Angeles, NCIS: Hawaii, NCIS: New Orleans, NCIS: Sydney And NCIS: Origins.

Speaking to PEOPLE in 2019, Harmon revealed the secret to his success, which he attributed to his late father’s advice.

“My father taught me: If it’s not true, don’t worry,” he said NCIS Star said of his father, who died in 1990 at age 70. “I come from a working-class family and am proud of it. You have to get up every day and just push yourself.”

At the time, Harmon explained that although his father passed away nearly three decades ago, he continued to follow his father’s advice.

“Work your ass off and don’t let the effort show,” he said. “Also, treat people equally, not based on who they are or what they are. Show them general kindness. Don’t let their fame or profession color you. I don’t get too excited when people blow smoke up my ass. You have to stay honest.”

Harmon serves as narrator and executive producer NCIS: Originswhich airs Mondays at 10 p.m. ET on CBS.