The No Doubt frontwoman hosted a charity event, which Obama and her security detail attended in 2012, and admits she was worried about how her children would act around such important people.
She says, "(Kingston) was maybe like six at the time and he didn't really get it, he knew she was important... but he was so worried about having strangers in the house.... He was like, 'I don't want people in our house that I don't know...'
"So they were like, 'Ok, when the first lady gets here, we want all of the children lined up and everyone needs to be standing here for at least 10 minutes waiting,' and I was like, 'Ok, good luck, because these kids are not going to stand here for at least 10 minutes.'
"So they're standing there rolling around, it's like chaos and she gets there and she walks in and then the big one... steps on the little one's hand in front of her, then I have to pick him up and I have this pink silk top on and he drools all over it.
"They're, like, screaming and crying and we are trying to take a picture, but she was so awesome. She was like, 'Look, I got kids, I totally get it'."
But Kingston made mummy proud by the day's end when he crafted a gift for the family's distinguished guest.
Stefani adds, "He went into his room and made some clay sculpture and gave it to her at the end and was like, 'I'm sorry'."