Kate, who is expecting her second baby in April, was pictured arriving at the group's hut in Poplar and was dressed in a pair of black skinny trousers teamed with a Scouts' zip-up hoodie.
Rather than going the whole hog and completing her look with trainers, the Duchess of Cambridge was rocking a rather stylish pair of flat knee-high boots and had her hair loose in her famous blowdry.
Kate's visit to meet the 23rd Poplar Beaver Scouts was a surprise one and she got stuck in with helping the children learn about living with disabilities for the Scout Association's 'Better Prepared' campaign.
In a serious of snaps taken inside the venue, Kate can be seen wearing a blindfold - made out of a Beaver neckerchief - and attempting to cut up a plate of food while sporting a boxing glove on one hand.
The Royal, who has previously volunteered with the Scout Association, appeared to be having a great time helping the children and presented them all with a new badge before the meeting finished.
Last week, Kate accompanied her husband Prince William on a brief visit to New York.
While there, the Duke and Duchess attended a basketball match in Brooklyn and were pictured in the stands with Beyoncé and husband Jay Z.
In April, the couple are due to welcome their second child together having announced that Kate was pregnant back in September. Although she initially suffered from hyperemesis gravidarum - severe morning sickness - Kate is now looking in good health.
Kate and William are already parents to son George, born in July 2013.
Celebrities congratulate William and Kate on their second pregnancy: