Rihanna Lip-Sync? [VIDEO] Chris Brown's Ex High on Weed, Drunk During Singapore 'Diamonds' World Tour Concert? Twitter Fans Disappointed

Did Rihanna lip-sync during her "Diamonds" World Tour performance in Singapore on Sunday evening (Sept. 22)? Apparently several Twitter fans think she did... many of them also claim that she was high as a kite!

@iamcolleen: "Kinda expected more from Rihanna but all that lip syncing was........."

@ievandarwin: "Rihanna looked ratchet as hell, she can't dance and I swear she looks drunk or high on some drugs on stage the whole time."

@st_evel_ai: "SPOILER ALERT: Rihanna is lip-syncing. From the Ex-soundman next to me. Plus red light isn't on, on her mic. She walks like Rihanna though."

@patolaaaaa: "Rihanna is lip syncing plus she's late! #wtf."

@georgiekitch:, "Had high hopes for #Rihanna tonight but she was absolutely awful!!! #SingaporeGP."

@christopherb417: "Lol at folks in Singapore surprised that Rihanna was high & lip-syncing at her show! #duh #overrated."

@GLENDONphan: "Rihanna's either drunk or pretty f#cking high right now."

@chopstuck: "If Rihanna was lip-syncing she did a peefectly good job during the parts where she was like hallucinating."

@ivanborgy: "I'm disappointed for those who paid 26K for Rihanna's Concert because the girl was lup-syncing. Not worth the penny. Huhu."

What do Mstars fans think... was RiRi indeed "faking" it?