He and a pal, both 31, allegedly attacked a waitress, 20, after a Wolverhampton gig. He denies it.
A fan claimed the ex-JLS idol raped her after she and a friend were invited to his hotel room.
A source said: “She and her friend are massive JLS and Oritsé fans.
“They agreed to go back to his hotel with him and a friend he was with.
“They eventually left the room but outside they realised they left behind coats and — more importantly — a handbag with a purse in it containing taxi money to get home.
“One girl knocked on the door saying she wanted to retrieve her stuff and was let back in.
“It’s then she says she was raped. “Police were called to the hotel shortly afterwards to a report of rape. Williams was arrested there.”
The singer, 31, was bailed several times as cops probed the December 2016 incident at Wolverhampton’s four-star Ramada Park Hall. It followed his gig at the city’s Gorgeous club to promote solo album Waterline.
Officers last night revealed he has now been charged with rape and his friend with assault.
After his initial arrest, the singer’s management firm 10 Worlds Music said: “Oritse denies the allegations.
“The matter is in the hands of the police and it would be totally wrong for us to comment any further.”
Dad-of-one Williams then quit ambassador roles at the MS Society and music therapy charity Nordoff Robbins.
He said: “With great sadness I’m stepping back from charity work.
“Unfortunately there has been a lot of speculation regarding events. It’s likely to be unhelpful to the charities.
He and JLS pals Aston Merrygold, Marvin Humes and JB Gill shot to fame on X Factor in 2008 despite finishing runners-up to Alexandra Burke.
They sold ten million records, including five Brit No1 singles and four top three albums. After their 2013 split Williams set up a music firm and sang solo under stage name OWS.
Last night West Mids police confirmed: “We’ve charged two men with sexual offences after an allegation of rape at a Wolverhampton hotel.”
They confirmed them as Williams, of Croydon, South London, and Jamien Nagadhana, of Hounslow, West London.