PC Ireland Murdock allegedly attacked his victim in Lambeth while he was off duty on 25 September last year.
He was arrested on 11 January and will appear at Croydon Magistrates’ Court on Friday.
PC Murdock has been suspended from duties. The Met’s Directorate of Professional Standards has been informed, as has the Independent Office for Police Conduct.
Specialist officers are supporting PC Murdock’s alleged victim, Scotland Yard said.