Published Tuesday, 04 December 2012
The Saturdays singer, who is due to give birth next year, joined her partner and his JLS bandmates to meet youngsters at a hotel in the UK capital.
The stars played games with the kids at the event, staged by the Rays of Sunshine organisation, which grants wishes for sick children.
The mother-to-be then uploaded pictures from the bash to her Twitter page.
JLS star Aston Merrygold tells the Daily Star newspaper: "If you can give up a couple of hours of your time to help these kids it's brilliant. They are incredible, and it's wonderful to be able to put a smile on their faces."