Directed by Mani Ratnam, "Dil Se" was a love story set against the backdrop of insurgency in North East.
"The one u love the most is sometimes not loved by most... but the love doesn't change. My favourite.
#18yearsofdilse," Shah Rukh captioned the short video, which shows him saying a romantic dialogue and concluding it with a "thank you" to everyone for the film.
"Dil Se" is counted among 50-year-old Shah Rukh's best works till date.
The movie also starred Manisha Koirala and Preity Zinta (in her Bollywood debut).
Preity, 41, also shared her feelings about the film from where "it all started" for her.
"#18yearsofdilse Thank you @iamsrk @mkoirala & #Manisir 4my journey from Criminal psychology to movies. #destiny.
#18yearsof_???_?? ?? This is how it all started (sic)," she posted.
The film's writer and one of the producers, Shekhar Kapur, tweeted, "Not that I did much to help, but Mani Ratnam was kind enough to keep my name as producer. Proud of #18YearsOfDilSe @iamsrk @arrahman.