The 26-year-old singer and his bandmates - Oritse Williams, Aston Merrygold and J.B. Gill - are getting ready for their final ever concerts in December and the release of their last album 'Goodbye: The Greatest Hits' and as they start to look back on their career one night sticks in Marvin's mind.
The 'She Makes Me Wanna' hitmaker insists nothing will top the night they went home with the gongs for British Breakthrough and British Single - for 'Beat Again' - at the 2010 BRIT Awards.
When asked to name his favourite moment in JLS, Marvin told BANG Showbiz: ''That we're Brit Award winners I think. We were the first 'X Factor' act to win at the BRITs ... I remember when I was 10 years old I got interviewed by my local newspaper and I said when I was older I wanted win at the BRITs and we did it.''
Despite the decision to go their separate ways, the boys - who shot to fame on 'The X Factor' in 2008 but lost in the final to Alexandra Burke, coming third behind Eoghan Quigg - are certain they will remain close friends forever.
Marvin said: ''Once we split of course we're all going to busy individually so we aren't going to be all together as much as we want but we will definitely still see each other lots. It's going to be like we haven't split up, you know, socially because we'll still be together.''
Oritse agreed with his friend, adding: ''We're still meeting up and we're still going out and that's going to continue. Our families are all one big family as. Family is family and that doesn't change.''
JLS will be releasing a live DVD of their concert at The O2 in London and 'Goodbye - The Greatest Hits Tour DVD' is available to pre-order now.