Content warning: This news article contains discussion of sexual assault.

Nelly is under criminal investigation for sexual assault that allegedly took place in the UK late last year. 

As TMZ reports, the incident allegedly occurred after the US rapper's concert at Cliffs Pavilion in Essex on 5 December where he invited a woman to his dressing room. 

It is alleged the 43-year-old sexually assaulted the woman and attempted to force her to perform a sex act on him. 

Essex police are now investigating the allegations. 

Nelly has denied the accusations through attorney Scott Rosenblum. 

"These allegations arose after Ms Green amended her suit for money to include a reference to these claims," Rosenblum told TMZ.

"The fact that the police are investigating these claims is not new information and Nelly welcomes a thorough investigation. Nelly is confident that once investigated, these claims will be determined to be disingenuous.

"Nelly was accompanied by his girlfriend during this tour and she was at his side throughout. It is important that police investigate every allegation of this nature."

The news comes just months after Nelly denied allegations of sexually assaulting another woman on his tour bus.

If you or someone you know is impacted by sexual assault, domestic or family violence, call 1800RESPECT on 1800 737 732 or visit 1800RESPECT.org.au