Chicago's hip-hop and R&B radio station 107.5 WGCI held its Summer Jam concert over the weekend—and they came through with an unexpected guest appearance from Chance the Rapper.

The big event, held at the Wintrust Arena in Chicago, saw performances from Yo Gotti, Teyana Taylor, G Herbo, Queen Naija and Gucci Mane, the latter of whom was followed by Chance, who made his surprise entry and stuck around to perform three songs.

Perhaps fans should have seen it coming though. The show, which also included performances from Shordie Shordie, Ann Marie and Polo G, was co-sponsored by Wendy's, which brought back its spicy chicken nuggets earlier this month specifically because Chance the Rapper tweeted about it and prompted a social media campaign.

See photos from Summer Jam below, by Dan DeSlover.