News of Smittle's death was confirmed via Brooks' daughter, August, on Instagram.
"My beautiful Aunt lost her battle with Cancer early Saturday morning," the country music star's daughter posted on Monday night. "So happy she got to meet my beautiful daughter! We love you and miss you Aunt Betsy!"
Smittle, who served as a bass player for her famous half-brother, died on Saturday, Nov. 2, according to KWTV News 9 in Oklahoma City, Okla. She toured with Brooks and his band, Stillwater, for many years, and even appeared on Brooks' albums such as "Ropin' the Wind," and in 1994, Smittle released a solo album entitled "Rough Around the Edges." The guitarist was also a gay marriage advocate who often performed at gay pride events throughout Oklahoma.
On Twitter, many music lovers are mourning the loss of Smittle, and are extending sympathies to Brooks and his family.
"Sending our condolences to Garth Brooks, who is mourning the loss of his half-sister," wrote Country Music is Love.In addition to Betsy, Brooks has three other older half-siblings as well as an older brother, Kelly.
Meanwhile, Brooks is best known for his hit songs "Friends in Low Places," "Two of a Kind, Workin' on a Full House," and "Unanswered Prayers," among many others.
The 51-year-old singer is married to country music singer Trisha Yearwood. The couple have homes in several U.S. cities, but spend most of their time in the suburb of Tulsa, Owasso, in Oklahoma.
Many country music stars will join this weekend at the CMA Awards this Wednesday, Nov. 6. Brad Paisley and Carrie Underwood will host the live awards show, which has been deemed "Country Music's Biggest Night." It airs in ABC Wednesday at 8 p.m. EST.
