How to tell children I'm pregnant.

I have two little girls, 6 and 4, and we are trying to decide how to tell them my boyfriend and I are pregnant.

I know they will be excited as they have asked us when we are going to have a baby and even told us what they want: "I want a baby brother!". I'm 8 weeks as of yesterday and we have already told my parents and his. My mom accidentally spilled the beans to my brother before I got to tell him. His dad got excited and told a bunch of people and now a lot of people know 🤦🏼‍♀️ but we haven't told my daughters.

I know it's early but I want to tell them soon before someone accidentally tells them or they overhear it and it takes the fun away from me and my SO telling them. I have my first US two weeks away.

Do any of you guys have any suggestions about telling them? How to and when? Any fun ideas or anything?