Robbie joined Take That for the second time in three days this week when he sang with his old bandmates at a gala performance of The Band.
Marking the musical's West End debut, the evening was put on to raise funds for the Elton John AIDS foundation, which funds frontline programmes that help alleviate the pain of those living with, affected by or at risk of HIV/AIDS.
Speaking about the possibility of singing alongside Gary, Mark and Howard again, Robbie said 'if we're in the same town at the same time, then I'll hop on stage. There's always an open mic at my gigs and there's an open mic for me at their gigs too.'
The Band will run at London's Theatre Royal Haymarket until 12 January 2019, so get your tickets before they're all booked up!
Robbie will follow in the footsteps of his bandmates when he headlines BST Hyde Park on 14 July 2019. Tickets for what will be his only open-air show in the UK next year are on sale now, so grab yours and we'll see you in the summer!