Justin Hartley was sexually harassed by a fan in a restaurant.

The 'This Is Us' actor was horrified when he was enjoying dinner with friends in Chicago, only to be interrupted by a ''screaming'' woman who started kissing him.

He said: ''This woman - who I don't know, a stranger to me - recognised me and started screaming, going crazy. She ran over and started kissing me.''

Justin tried to back away from the woman and asked her to take a step back, but she persisted.

He continued: ''I said, 'You do not walk up to people that you do not know and put your mouth on their face. If I did that to you, I would be in prison. Please do not do that. And not that I'm trying to teach you life lessons, but I feel like this is a really good one for you. Don't do that to anybody ever again.' ''

The woman seemed embarrassed after being reprimanded but the 41-year-old actor tried to smooth things over.

He told America's Good Housekeeping magazine: ''We had a little breaking of bread, if you will, and everything calmed down.''

However, the fan - who Justin recalled had been ''drinking a lot'' - later returned to his table to ask for a photo, and didn't take kindly to her request being refused.

Justin explained: ''I said, 'I'm good.' I'm usually really good with photos, but I'm, like, 'I'm not taking photos with you after you sexually harassed me. I'm good without a photo.'

''As she was leaving, she was, like, 'Justin Hartley is a jerk,' but not really jerk -- something more foul. I was, like, 'You've got to be kidding me.' ''

And the actor thinks the unnamed woman should be ''ashamed'' of her actions.

He slammed: ''I'm not afraid to say this, because I think she should be ashamed of herself.''