Taylor Swift: Meet the Celebrities She's Brought On-Stage During Her 1989 Tour

The list ranges from Julia Roberts to Chris Rock to Alanis Morissette.

For weeks, the "Bad Blood" singer has invited celebrities to join her on stage, but since coming to L.A. for a series of shows, she's turned things up a notch.

"I don't know how to process any of the events of tonight," she wrote of last night's concert.

All across the country, however, other stars have joined Swift, 25, for some of her biggest songs (and, in the case of some musicians, a few of theirs!), too.