Sisters surprised by adopted baby brother under Xmas tree

One of the girls can be seen crying after realising that she has a brand new baby brother. Photo / Facebook

For three young sisters, it's the gift that trumped iPads, Frozen merchandise, and likely many Christmas presents to come.

Captured in a heartwarming video gone viral is the moment Chloe, Emma and Maci Solstad are surprised with an adopted baby brother under their Christmas tree.

Their parents, Courtney and Steve Solstad, who live with their now four children in Dallas, Texas, wanted to create a Christmas their girls would never forget.

The footage shows the girls bursting into tears of joy upon discovering their new sibling, Nathan, nestled under the tree.

One exclaims, "I'm going to pee my pants" in the video which has been viewed over 500,000 times.

Mum Courtney wrote alongside the video posted to Facebook: "The girls knew nothing about Nathan until this.

"We met them at the door and told them that we had been out Christmas shopping and got them a gift to share... and it was under the tree!"

- nzherald.co.nz