It is the remake of 'The Invisible Guest (2016)', a Spanish film.

The Principal photography of the film began on 14 June, 2018 in Glasgow, Scotland.

Bachchan's dialogue in the film related to 6 and 9 analogy was also used in his Aakhree Raasta (1986) and Suhaag (1979) .

Bachchan's name in the movie is Badal which is an anagram for Badla which is movie title.

In one of the scene filmed to show Amruta Singh's home, the poster of Sidney Lumet classic '12 Angry Men' is visible. Like this, that film too was based on the theme to search the real truth among multiple point of views.

Tapsee Pannnu's second film with Amitabh Bachchan since Pink (2016). In both the films, he plays the role of lawyer hired by the character of Pannu.

Amitabh Bachchan's first film under Shahrukh Khan and Gauri Khan's production company, Red Chillies Entertainment.

Sujoy Ghosh had the title "Badla" registered with him for a few years. He had attempted to make a film with Amitabh and Naseeruddin Shah with the title Badla in 2012. The film was shelved for unknown reasons.

Amrita Singh and Amitabh Bachchan acted last together in Akayla (1991). They were also parts of Shootout At Lokhandwala (2007), but did not share a scene.

On 11 February 2019, Shah Rukh Khan, whose production house Red Chillies Entertainment is producing the film, tweeted two first look posters of the film, one with Bachchan's character and another with Pannu's.

Film did well overall but Amitabh Bachchan wasn't happy with everyone's reaction as no body was praising the film.As the film journalist were only penning about Gully Boy and Total Dhamaal which released few days earlier.

Shahrukh Khan was to make cameo in the film.But later dropped it.

The card used to access the bank system would not work because it was reported all over the news that the person the card belongs to is missing/presumed dead. In this case, the card would have been disabled by the bank.

The music of the film is composed by Anupam Roy, Clinton Cerejo and as a guest composer Amaal Mallik.

In the original, the main lead was a boy and Amitabh's character was a girl while Amrita Singh's character was a man.

Ram Gopal Varma had planned a horror film titled "Badla" with Randeep Hooda and Urmila in 2006. All plans were dropped so Ram Gopal Varma could make RGV Ki Aag.

On 12 February 2019, Red Chillies Entertainment have posted the official trailer on Youtube.

Badal was Amitabh Bachchan's character name in the 1975 film Zameer.

For the first time, Amitabh Bachchan is revealed as an unimportant character.

Manavi kaul did talk to Amitabh sir on phone , in front of taapsee but surprisingly couldn't detect d wrong !!! Also since he only hired him , so he knew Amitabh Wil b coming 3 hrs later !!