The 'Oh Love' band cancelled a concert in Bologna, Italy hours before the gig was to take place on Sunday (September 2) when Armstrong was hospitalised.
Armstrong apparently remained under doctor's care for a mystery illness for several hours, but has since been discharged.
A spokesperson for Green Day has confirmed to MTV News that the band will still honour their scheduled VMAs performance.
Green Day are expected to arrive in Los Angeles later today (September 5) to begin rehearsals for the show.
One Direction, Pink, Frank Ocean, Rihanna, Taylor Swift and Alicia Keys will all play the VMAs as well.
Kevin Hart hosts the 2012 MTV Video Music Awards live from Los Angeles, now airing from 8pm to 10pm ET to accommodate US President Barack Obama's Democratic National Convention speech.
Watch Green Day's 'Oh Love' music video below: