Rihanna recently resumed her Diamonds World Tour after nearly a seven-week summer break and fans have accused her of lip-synching and being intoxicated during her Singapore concert Sunday night.

The 25-year-old Bajan beauty performed at the F1 Grand Prix on Sept. 22 and afterwards fans took to Twitter to blast the singer for being "disappointing," "high on weed" and not singing live. A source at the concert said Rihanna's microphone wasn't on when she performed.

Steve Lai, newsreader for Channel NewsAsia, reportedly tweeted, "SPOILER ALERT: Rihanna is lip-synching. From the ex-soundman next to me. Plus red light isn't on on her mike. She walks like Rihanna though."

"Am sure Rihanna just forgot the words and mouthed 'sorry.' At least she's singing. Dipping in and out of a backing track at least," he added.

According to Mirror, a fan tweeted, "@Rihanna Yo mullet! Singapore is too classy for your s**t. Go lip-sync somewhere else!"

Another fan even joked and said the singer was doing the crowd a favor: "LOL @ people complaining about Rihanna lip-synching during her concert... she's doing you a favour!"

Rihanna made recent headlines after she posted a picture of a monkey, which led to an arrest of two men.

"Look who was talkin dirty to me!" she wrote of the picture that was posted on her Instagram account. 

Local police were reportedly monitoring her social media account. A 20-year-old man and a 16-year-old boy were taken into custody and could face charges of possession of protected animals. If convicted, they could face up to four years in prison and a $1,300 fine.

Tags: Rihanna Diamonds World tour