Jimmy Kimmel broke down in tears as he remembered his best friend and bandleader Cleto Escobedo III in an emotional opening monologue on Tuesday night.

Hours after announcing the death of Escobedo via social media, the talk show host delivered a 22-minute opening monologue on Jimmy Kimmel Live! in which he tearfully paid tribute to the Cleto and the Cletones leader, who died on Tuesday aged 59.

Immediately crying, Jimmy told the audience, "We've been on the air for almost 23 years, and I've had to do some hard monologues along the way. But this one's the hardest because late last night, early this morning, we lost someone very special who was much too young to go, and I'd like to tell you about him, if you don't mind."

The 57-year-old then recalled how he met Cleto in 1977 when his family moved into a house across the street from him in Las Vegas, and they became "24/7" friends who liked the same things and fit together "perfectly".

After reminiscing about their evolving friendship - accompanied by throwback photos - Jimmy remembered how he wanted Cleto, a "phenomenal saxophone player", to be his bandleader when he landed his talk show in 2003.

"'My best friend from growing up plays the saxophone, he could lead the band,' wasn't a great pitch," Jimmy acknowledged, before explaining how Cleto and his father Cleto Sr. auditioned for ABC boss Lloyd Braun.

"(Braun) said, 'I love it!' And he got up and left. And we've been working together every day for almost 23 years now," he shared.

The TV personality was overcome with emotion on and off throughout the monologue and the camera often cut to Cleto Sr., who sat with the band, and Cleto's mother in the audience.

"Everyone here at the show, we are devastated by this," said Jimmy, visibly and audibly upset. "It's just not fair. He was the nicest, most humble, kind and always funny person."

Jimmy added that he was "heartbroken" to lose Cleto but felt "lucky" to have had him "literally at my side for so many years".

He explained that he taped the episode because he wanted to talk about his best friend, but he will take the rest of the week off.

The star previously cancelled an episode last week to tend to Cleto as the musician's condition worsened.