7:44am PT by Natalie Weiner, Billboard
Watch Taylor Swift and Haim Perform "Hot in Herre" With Nelly in St. Louis
Taylor Swift played the second of two shows at St. Louis's Scottrade Center last night (Sept. 29) and, well, things got a little heated — in a good way.
To celebrate Haim's last night on the tour, Swift invited them to join her onstage as backup dancers for Nelly, who, naturally, performed his 2002 hit "Hot in Herre" for the hometown crowd.
Watch Taylor's snippets of their performance below, which include very careful choreography and emphatic singing to the song's unforgettable chorus.
According to Taylor, it was "the highlight of [their] friendship thus far" (pretty understandable).
This isn't even the first time Taylor has invited the rapper onstage — check out their 2013 duet of "Hey Porsche" below, as well as their 2011 (!!!) performance of "Just a Dream."
This article originally appeared on Billboard.com.