The chart-topping quartet were closing the Main Stage at the London festival, held at Victoria Park, when they surprised the 50,000 strong crowd by inviting the 'Bonkers' hitmaker onstage for their new collaboration 'Love Ain't Just A Word'.
During their performance, the lads - who, along with Dizzee, were raised in the capital - shouted to the crowd: ''This is our home!''
Ella Eyre - who was performing alone earlier in the day - also joined Rudimental onstage to perform their hit single 'Waiting All Night'.
Another Londoner, Ella said: ''It's good to be back in my home town''.
The festival-goers - who were treated to Tia Espresso Ice Coffees from Tia Maria's Cool Beans milk float at the event - went wild for Rudimental's older hits from their debut album 'Home', like 'Feel The Love', which they closed the festival with.
However, their most recent singles 'Never Let You Go', 'Bloodstream' and 'Rumour Mill' got the crowd just as pumped, showing there's no sign of the band fading into obscurity any time soon.
Throughout the day, the Main Stage also saw newcomer Karen Harding kick off the festival, performing her debut hit single and the MNEK-produced 'Say Something', as well as deep house duo Blonde, who got the crowds dancing with their summer anthem 'All Cried Out'.
Skepta took to the stage later, managing to get the audience jumping and moshing in three separate pits as he performed hits like 'That's Not Me' and 'Shut Down'.
Meanwhile, Mark Ronson's DJ set seemed a tad underwhelming, as he played his ''favourite track of the summer'', D.R.A.M's 'Cha Cha' as well as a repeat of 'Shut Down', although his massive hit 'Uptown Funk' got the crowd going wild and dancing.
'Smalls Change (Meditations Upon Ageing)' arrives in April.
The two awards have made for a great 72nd birthday present for the country music icon.