Philadelphia, Pennsylvania - Marvel star Robert Downey Jr. made an unexpected visit to watch Olivia Rodrigo perform in Philadelphia as the GUTS World Tour resumed over the weekend!

After a few weeks off, the 21-year-old pop star picked up her sold-out concert series at the Wells Fargo Center on Friday.

Enjoying her show were RDJ and Justin Theroux, the latter of whom dropped a few snaps from the concert via his Instagram.

The duo was joined by Justin's girlfriend, The Gilded Age star Nicole Brydon Bloom, and her sister, Ava.

Celebrities Has Mariah Carey found new love with a much younger musician?

Ahead of Friday's show, Olivia shared her excitement with a TikTok alongside her tour crew with the caption, "3rd leg of the #gutsworldtour starts 2niteeee."

The get him back! artist spent some time in New York City before traveling to the City of Brotherly Love on Friday.

Olivia was seen strolling arm-in-arm with her rumored boyfriend, British actor Louis Partridge, on the streets of the Big Apple, and the two weren't shy about showing PDA, per PEOPLE.

Though the pair haven't explicitly confirmed the status of their relationship, Louis was the first to break his silence on the romance in an interview with British Vogue earlier this year.