'That's your baby brother!' Big sisters find amazing surprise under the Christmas tree

Three little girls got an amazing surprise this Christmas -- a new baby brother!

Courtney Solstad shared a video on Facebook saying that her daughters had no idea Nathan was being adopted, so they put him under the tree to surprise his big sisters.

Solstad said on Facebook: "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!"

The video has been viewed on Facebook more than 130,000 times.