The action-comedy directed by Rohit Shetty also stars Deepika Padukone, who plays a South Indian in the film, has dubbed in the typical southern accent.
This is the second collaboration between Khan and Padukone after the 2007 blockbuster "Om Shanti Om and the first collaboration between Khan and Shetty.
"Chennai Express" is about a man's journey from Mumbai to Rameshwaram and what happens along the way after he falls in love with the daughter of a don, played by Padukone.
SRK, 47, is back as Rahul, one of his most famous screen names, in this film.
In the trailer, SRK is seen taking fun potshots at himself and his previous films like the famous train sequence from "Dilwale Dulhania Le Jayenge".
He says, "Myself Rahul. Chaalis saal ka ho gaya hoon (I am 40). Normally iss age tak har kissi ke life mein adha ek twist to aa hi jata hain. Meri life mein bhi ek twist aya, bahut bara twist jisse meri life hi badal gayi (In this age normally everyone has some big twist in their life and so did I. And it completely changed my life."
The UTV Motion Pictures and Red Chillies Entertainment movie will release on August 8.
Keeping the impending promotions in mind, SRK has returned to Twitter after a gap of few months.
In his most recent tweet, the actor has praised his director friend Farhan Akhtar's latest production 'Fukrey'.