The Beatles legend was a surprise special guest at the concert on Saturday playing Wings tracks 'Coming Up' and 'Goodnight Tonight' with the Blur frontman.
Paul - who had earlier in the day been awarded the French Legion of Honour at a ceremony in Paris - also played bass on Rokia Traore's 'Dounia', while former Led Zeppelin bassist John Paul Jones took the mandolin.
Other highlights of the show - held at London's King Cross station - included Kano and Bashy joining John Paul for Led Zeppelin's 'Kashmir', Spoek Mathambo's reworking of Joy Division's 'She's Lost Control' and Damon and Rokia Traore's spellbinding duet on Gorillaz's 'On Melancholy Hill'.
The gig was the final stop for the Africa Express, a collective of musicians - including former Libertine Carl Barat and Jon McClure - who had traveled across Middlesbrough, Glasgow, Manchester, Cardiff and Bristol on an especially chartered train playing special one-off shows at schools and venues.
The tour was part of the London 2012 festival to celebrate the Olympic and Paralympic games.