The Prime Minister's wife, Samantha Cameron, has launched a charity Christmas jumper day to raise money for children.
Traditional Christmas jumpers are the sort of thing your Granny might knit, with colourful Christmas animals and patterns.
They used to be really uncool but now they are coming back into fashion.
Save the Children is behind the idea and is asking everyone to wear festive knitwear on December 14.
Send us your Christmas jumper pics!
Do you have an amazing Christmas jumper? Maybe someone in your family has made you one that you have to wear on Christmas day.
Send your pictures to firstname.lastname@example.org and include a telephone number so we can ask permission if we want to use your photo.