Joshua Lodge will be on the Sex Offenders Register for two years
Harry Potter star Rupert Grint has condemned a guest at his 18th birthday party who received a police caution for a sexual assault on a girl.
Joshua Lodge, 19, had denied a charge of sexual activity with a child in September last year.
Lodge, a school friend of actor Rupert, was arrested after the event at Watton-at-Stone near Stevenage, Herts.
Mr Grint said: "I am totally appalled and disgusted by the actions of Joshua Lodge. I am 100% behind the victim."
Lodge was caught with the girl in an outbuilding at the party and ordered off the premises, St Albans Crown Court was told.
Cautioned for offence
Prosecutor Ann Evans said: "The offence was such that two teenagers were at a private party where unfortunately too much drink was taken and a caution would be appropriate.
"After considering the matter over the last few days and, having taken the opportunity to speak to the victim and her family, the Crown propose the defendant is cautioned for this offence.
"The defence is prepared to accede to this."
Mr Grint, who plays Harry Potter's sidekick Ron Weasley in the films, immediately issued a statement through Hertfordshire police condemning his former friend.
The caution means that Lodge's name will now appear on the Sex Offenders Register for two years.
St Albans Crown Court was told that Lodge, of Ruskin Close, Cheshunt, Hertfordshire, was of previous good character.
Judge Marie Catterson formally recorded a not guilty verdict.
The victim's family said in a statement: "Given the circumstances surrounding the incident a caution and placements on the Sex Offenders Register is appropriate punishment.