[7][8] The film stars Dhanush in the title role along with Amitabh Bachchan and debutante Akshara Haasan.

Danish and Akshara go to a voice hospital to get his check-up, but doctors declare his vocal chords are fully paralyzed and cannot be treated.

Danish makes two films and turns out to be a hit actor to which Amitabh realises was only because of him and an ego problem between the two starts to rise.

[16] Bachchan lent his voice to Dhanush, who plays a dumb aspiring actor in the film.

[17] The film's title derived from the duo's names in which 'Sh' from Dhanush was added as a prefix to Amitabh, therefore becoming Shamitabh.

[18] Besides the lead cast,[13] it was confirmed in February 2014 that actor Rajeev Ravindranathan would appear in a small role in the film.

[21][22] Later it was reported that not only Mahesh Bhatt, but Karan Johar, Anurag Basu, Rakesh Omprakash Mehra, Rajkumar Hirani, Gauri Shinde, along with lyricist Javed Akhtar and producers Boney Kapoor and Ekta Kapoor would do cameos in the film.

[29][30] The crew shot some scenes at the Seven Hills Hospital, the same place where Bachchan underwent two abdominal surgeries and saw the birth of Aaradhya, his granddaughter.

[32] The team took a break in mid-July 2014 to celebrate Dhanush's birthday and the success of his 25th film, Velaiyilla Pattathari (2014).

[36] The film's cinematographer P. C. Sreeram was fascinated by Akshara's acting capability and lack of nervousness while shooting with Dhanush and Bachchan and lauded her as a "woman of substance".

A video trailer of Bachchan sitting in a toilet and singing "piddly si baatein", a catchy, peppy song while holding the script, was released on 31 December 2014.

[50] Srijana Mitra Das of The Times of India gave it 3.5 stars out of 5 and stated, "Shamitabh has a doubly dramatic act – but less emotion".

[52] Rajeev Masand of IBNLIVe gave the movie 2.5 stars stating "The promising film comes undone by the curse of the second half".

The Guardian gave average reviews describing the movie "Amitabh Bachchan in affectionate but incoherent satire".