The tennis star, who made a surprise appearance during Kendrick Lamar’s halftime performance, posted behind-the-scenes photos from her rehearsals

Williams’ appearance in the halftime show is also raising eyebrows because Lamar brought her out on stage during a song that’s commonly known as a diss to Drake. Lamar and Drake feuded over the years, culminating in a series of diss tracks about one another last summer — and a lawsuit.