The actor says he was jumped on by the ex-journalist, who reportedly grabbed at him while Brad was joining his fiancée on the red carpet.
“I was at the end of the line signing autographs, when out the corner of my eye I saw someonestage-diving over the barrier at me,” Brad, 50, told People.
“I took a step back; this guy had latched onto my lapels. I looked down and the nutter was trying to bury his face in my crotch, so I cracked him twice in the back of the head – not too hard – but enough to get his attention, because he did let go.
“I think he was then just grabbing for a hand hold because the guys were on him, and he reached up and caught my glasses.”
The Hollywood star continued, “I don't mind an exhibitionist. But if this guy keeps it up he's going to spoil it for the fans who have waited up all night for an autograph or a selfie, because it will make people more wary to approach a crowd.”
“And he should know, if he tries to look up a women's dress again, he's going to get stomped,” he added, referring to one of Vitalii’s earlier antics, when he accosted America Ferrera on the red carpet in Cannes.
At the time that Brad's statement was released, his future wife was making a special appearance in Shanghai to attend a press conference for Maleficent.
Fans of the Oscar winner were this week saddened to learn her acting career might soon be coming to an end.
In an interview this week, Angelina suggested that an upcoming appearance as Cleopatra could be her final film role.
“I imagine the preparation for it is going to be big,” she said of the project. “It's one of those that you think maybe that's the one you put everything into and that's where you end it, that's where you finish – in a great way. What could you do beyond that one?”
It’s not the first time Angelina, 38, has hinted her acting might soon take a back seat.
Last month she revealed she wanted to focus more on her directing and her humanitarian work as a special envoy for the United Nations High Commissioner for Refugees.
“I've had a wonderful career and I'm very happy to have had all the opportunities to tell stories and work for as long as I have,” she said.
“I'm sure there will be more films but I am happy I am able to be selective and have fun with characters like this. But I would like to focus on writing and directing, and above all I would like to focus more on my work with the UN.”