Wilkinson was present for the week's last training session at Tokyo's Fuchu Asahi Football Park on the eve of the Springboks clash at International Stadium Yokohama.
Dressed in a grey T-shirt, black tracksuit bottoms and orange boots, he watched and gave advice as Farrell and Ben Youngs practised drop-goals in expectation of a tight encounter between the sport's top two ranked teams.
Farrell leads England into the climax to Japan 2019 from inside centre having recovered the dead leg sustained against New Zealand with Youngs and George Ford forming the half-backs.
Wilkinson famously struck the extra-time drop goal that clinched a 20-17 victory over Australia in the 2003 final - the nation's only World Cup triumph - and also started the global showpiece four years later.
The 40-year-old works with Eddie Jones' squad on an consultancy basis, offering his technical expertise on kicking to the likes of Farrell, Ford, Youngs and full-back Elliot Daly.
It is believed that this is the first time he has been involved in an England training session in Japan and his wisdom has come as the clock ticks down on a seismic collision with South Africa.
And Farrell's World Cup favourites will enter the repeat of the 2007 final boosted by a good luck message from the Duke of Sussex that included a photo of his son Archie in a Red Rose jersey.
"As a group we've had a couple of messages from Prince Harry," Bath flanker Sam Underhill said. "He sent us a nice message of support, which was nice to receive. He showed his little lad in an England shirt, so that was a nice touch. I'm still waiting on my personal message!"