Former Santana Vocalist Alex Ligertwood Dead at 79

Alex Ligertwood -- who contributed lead vocals to iconic Latin rock band Santana over the years -- has died, TMZ has learned.

His daughter, Merci, announced the news Saturday, and the Brogan Agency confirmed the news Sunday, saying he "passed peacefully in his sleep with his doggy Bobo by his side" ... just 2 weeks after his final concert. He was living at his longtime home in Santa Monica when he died.

Brandon Paul, a guitarist who toured with Alex for the last several years as part of "Icons of Classic Rock," called Alex "a world-class professional" in a statement to TMZ. He went on ... "His voice was a force of nature -- soulful, from the heart, and legendary every single night. Beyond the music, he was an amazing human being and a dear friend."

Brandon added ... "Having a vocalist who worked with icons like Carlos Santana and Jeff Beck compliment my guitar playing is something I will carry with me forever." Clips of the pair sharing the stage together can be seen below.

Alex served as Santana's lead vocalist 5 different times between 1979 and 1994 and worked on albums such as 1979's "Marathon," 1981's "Zebop!," 1982's "Shango" and 1993's "Sacred Fire: Live in South America." He brought some of their biggest hits to life on stage, including "Winning," "Hold On," and "All I Ever Wanted."

TMZ has reached out to reps for Santana ... so far, no word back.

He was mourned by the music world following his death -- and one thing's clear -- he was beloved by all who knew him and his powerhouse vocals will be greatly missed.

He was 79.