This week has been a tough one for fans of live pop music. First, singer Rihanna this weekend cancelled her show in Boston due to laryngitis. Now, it appears that Justin Bieber has cancelled a concert that was scheduled to take place in Portugal tomorrow, March 12.

CBS News is reporting that Bieber’s second Lisbon, Portugal concert has been cancelled due to “unforeseen circumstances.” Current rumors are pointing to “logistical issues” with unions as the reason fro the concert cancellation. Bieber’s first Lisbon show, scheduled to take place tonight, is still a go and the singer began tweeting about the concert this afternoon:

There doesn’t appear to be any connection between the cancellation and the odd journey that Bieber endured in London last week. After being spotted walking London streets with his shirt off early last week and having shown shown up late for a concert, the pop star went on a Twitter tirade against “rumors” and “fake stories.” Rumors about the star’s “diva-like” behavior persisted, however, as he collapsed during one of his London shows later in the week. Bieber’s European tour will take him through France, Switzerland, Italy, and Germany in the coming weeks.