Rihanna angered fans by showing up more than two hours late to a concert this week in Antwerp, Belgium Radar Online reported Friday.

Rihanna is currently on the European leg of her Diamonds World Tour and had two shows in Antwerp that apparently left her fans demanding to know if she was under the influence of drugs. The Umbrella singer was accused of being "drunk", "stoned" and lip synching on Twitter. Rihanna was reportedly partying the night before and spent much of the afternoon shopping.

A music critic blasted the pop superstar for the Standaard newspaper in its review of the Wednesday concert.

"There was a wall of reinforced concrete between Rihanna and the public at Sportpaleis," Sasha Van Der Speeten wrote. "The pop icon played almost two hours on autopilot. ... It had the effect of a Valium overdose."

Der Speeten also said that the 25-year-old was more than just listless in her choreography. The critic felt there was no need for Rihanna to lip synch because she was not heavily exerting herself on stage.

"Besides the bored swaying back and forth like a drugged rich baby during We Found Love, she didn't dance," Der Speeten wrote.

Rihanna's fans, who called themselves The Navy, lashed out at their idol on Twitter.

"#Rihanna @ Sportpaleis: drunk or stoned? #Disappointing #Weird," Lisse van den Broek wrote Wednesday.

Another fan said that RiRi had no shame because she chose not to sing live.

"That does it Rihanna. We are out of here. I can't watch this any longer. You know no shame," Francis Saman wrote that same day.

The following day, Rihanna apparently disappointed her fans again. She was more than two hours late for the concert. Her fans once again took to Twitter to denounce her.

"Dear @rihanna, please do not return to Belgium until you have a decent album out and are willing to perform decently & on time!," Kenneth Strybosch tweeted Thursday.

In May, fans at the TD Garden in Boston booed the singer after she performed more than three hours after the start time.

Watch the footage below of Rihanna being booed in May.

Tags: Rihanna Diamonds World tour