While Offset was already slated to perform at the event in Palm Springs, California, the "Bodak Yellow" hitmaker sent fans into frenzy when she rushed to the stage to rap her verses in the couple's song "Clout".
The 26-year-old sported a multicloured Louis Vuitton cape jacket, and blue and purple hair with bunches styled into cute bows, while the Migos star, 27, hit the stage in a bandana-print T-shirt and cap to the back.
The couple, who are parents to 9-month-old daughter Kulture, danced throughout their lively performance and even paused mid-song for a kiss.
The "Please Me" rapper's unexpected performance came just two days after she surprised fans at Coachella by making an impromptu appearance during DJ Snake's set at the Outdoor Theatre on Friday.
The pair were joined by Selena Gomez and Ozuna for a performance of their collaboration "Taki Taki", and the star posted a photo of the foursome to her Instagram Stories afterward with the caption: "Coachella and I love them."
The rapper's appearance coincided with one-year anniversary of her debut album "Invasion of Privacy" and, speaking at the 2019 Spark Party in West Hollywood earlier that day, she confirmed plans to release its follow-up later this year.
"I'm starting to prepare myself now because I'm really trying to put out an album for this year," she said. "It's big pressure on me. It's like 'Aw snap, what the hell am I going to come up with?'"