The band are ambassadors of the charity, 'Rays of Sunshine', that grants wishes for terminally ill children, reported Sun Online.
The band has promised to continue working for the charity.
JLS had recently announced that they are splitting up after being together for five years. The band first appeared on the 'X Factor' in 2008.
JLS will finish their time together in December with a farewell tour and an album titled 'Goodbye'.