According to a report by Pakistan24.tv, the incident took place at the wedding of the son of politician Mohsin Leghari.
Fawad Chaudhry was also in the news in June 2019 for slapping journalist Sami Ibrahim.
Following the incident Fawad Chaudhry tweeted that people like Mubashir Lucman had no place in journalism, adding that it was important to expose such 'pimp journalists'.
https://twitter.com/fawadchaudhry/status/1213778727156559873?s=20
As the incident came in the attention of Twitterati, various reports as to the cause of the incident were reported. Journalist Mona Alam stated that Fawad Chaudhry slapped Mubashir Lucman because the latter accused him of being ‘involved in video-recordings with Hareem Shah’.
https://twitter.com/MonaAlamm/status/1213787111314350080?s=20