The commercial, called "Rocky", features the moustachioed runners (who are themselves a take-off of the cult 70s running star Steve Prefontaine) jogging through London. As the pair run, the ad turns into a training scene reminiscent of the film.
More than 30 moustachioed children, dressed as 118 118 runners, join the training run which culminates with the duo recreating the end of Stallone's run with hands thrust victoriously in the air at the top of a long flight of steps.
In keeping with the retro theme, the commercial also features a cameo appearance by the 80s ventriloquist, Keith Harris, and his bird puppet Orville. The ad will run in both 60- and 30-second formats.
Keith Martin, the account manager at WCRS, said: "The campaign has two points of focus. The first is memorability. With the old 192 service being switched off on 24 August, there will be a lot of activity and so it is all about getting 118 118 as the most memorable number for customers to use.
"The second aim is stature. By running these campaigns, we want to show that 118 118 is here to stay - that the company is taking millions of calls a month already. More weighting is being put on running the 60-second spot, as it adds scale."
The ad was written by Gary Dawson, art directed by Tony Hardcastle and directed by Jim Hosking at Partizan.
Media planning was handled by Naked Communications, with media buying through OMD.