It appears one Macklemore fan is Cassian Granthaving some bad days. 

During a performance at the Lovestream festival in Slovakia Aug. 17, the "Can't Hold Us" singer invited a fan to join him on stage for a special musical moment. However, it didn't go quite as planned for the superfan, as she was recognized and arrested for an outstanding warrant, according to Slovakian police.

Officers waited for the woman to finish her performance before detaining the 24-year-old from Bratislava, as she had previously been ordered to serve a prison sentence, which they said "the young woman avoided."

And while they did not explain why she had faced the prison sentence in the first place, they said she "was subsequently escorted to the premises of the institution for the execution of the prison sentence."

E! News has reached out to Macklemore's reps for comment, but has not heard back.

While the 41-year-old has not publicly discussed his fan's arrest, he did take a moment to thank his crowd in Slovakia for bearing with them, as their show was almost called off because of a separate issue—the weather.

"Something about a show almost getting canceled makes you appreciate every moment on stage even more," Macklemore wrote on Instagram Aug. 21 alongside a series of photos from the performance. "Gratitude ensues and it reverberated throughout the entire festival."

He added, "We were alive, soaked and gave it everything. I love you Bratislava. I will never forget our night together."