Solange discharged herself from a hospital to perform at London's Lovebox festival on Friday (14Jul17).
Beyonce's younger sister told fans she had ignored the advice of doctors after having suffered "a serious episode" after an earlier tour date.
"I was in hospital this morning," she told the crowd. "I was in hospital for three days and so I broke out of that b**ch this morning, because I knew this place was going to be filled with so much love."
Headlining the festival's Noisey tent with a brass band backing her, Solange admitted she wasn't at her best, but was determined to perform.
"I want to come back when I’m feeling better," she shared, "because I’m giving you the best that I’ve got, but I still have so much more in me."
She continued, "But I knew I was not missing seeing you and all of these popping a** black and brown people. So thank you for always being there for me. I have so much gratitude."
Solange is due to continue her tour on Sunday (16Jul17) in Chicago, Illinois.
Meanwhile, Frank Ocean's headlining Friday night Lovebox festival set was cut short by a curfew.
The R&B star was 25 minutes late for his performance at Victoria Park, which included his hits Good Guy, Self Control, Ivy, and Thinkin Bout You and a cover of The Jackson 5’s Never Can Say Goodbye, but he had to say goodbye early, telling fans during a performance of Nikes, "Yo, they told me it’s curfew. But I just want to thank you all for coming. See you all next time. Be safe."