Stacey revealed earlier this month that she was expecting her second child, and that the new baby was a complete surprise.
The expectant mum looked stunning in skin-tight denim leggings and a fitted shirt, and try as we might, we could not spot even the merest hint of a bump as she munched on goodies from the chocolate fountain and raced around after her three-year-old son, Zach.
She was lending her support to Samantha's new children's magazine, Sea Urchins, which aims to teach children from five to 15 all about marine life and conservation.
Samantha, a marine biologist, was inspired to create the mag after a life-long interest in animals and nature - something she said her grandfather instilled in her when he subscribed her to a wildlife magazine when she was seven.
Stacey said that she had "grown up" with Samantha's enthusiasm for animals, and "couldn't be more proud" of her achievements as a marine biologist.
She added that Samantha is now encouraging her son Zach, three, to develop an interest in wildlife and conservation. She said he already had "a great sense of respect and concern for nature" and the effect "we can have on the environment by all doing our bit".
Samantha took to the stage to thank Stacey and the rest of her family for supporting her endeavours, and also Dragon's Den star, Theo Paphitis, whose Ryman company sponsored the printing of the magazine's first issue. She told us that Sea Urchins was the result of a "life long dream," and that it was "overwhelming" and more than she "ever expected."
Sea Urchins is available for download at seaurchinsmag.com and free for visitors at Sea Life's 11 UK aquariums.
How well does Stacey look considering she must still be at the morning sickness and exhaustion stage of early pregnancy?