She's featured on three songs on his latest album "GNX." She caught Lamar's attention when she performed a tribute to her friend, the late Dodger pitcher Fernando Valenzuela, before Game 1 of the World Series.
She began recording just a few days later.
"This is (a) huge, huge thing happening in my life. My whole life dreaming to do many things with the music, with Mexico with the ranchera music..."
Barrera is from Sonora, Mexico, not far from from where Fernando Valenzuela's hometown. For just over 30 years, she's been singing her favorite music in Southern California and around the country.
She said working with Kendrick Lamar, and fusing the two genres of mariachi and rap, just simply works.
"I think everybody is talking good things about that collaboration and I'm very happy for that," Barrera said.
Her family home in the San Gabriel Valley is decorated with portraits of some of Mexico's greatest mariachi singers.
As she sings a ballad in the living room, she says she's hoping this will come of her work with the rap superstar.
"I hope many doors open for my career and doing more things that I've been dreaming for many years."
She said the collaboration with Kendrick Lamar will hopefully open even more doors for mariachi music to be used with other genres.