Beyonce Knowles and Jay-Z have reportedly filed an application to patent their daughter's name.

The couple field paperwork with the US Patent and Trademark Office last month to trademark Blue Ivy Carter's name to prevent others from profiting from the moniker or it is thought they might want to reserve it in case they decide to use it on a line of products in the future, the Washington Post reports.

According to reports, two other people have attempted to submit applications to trademark the name but they were thought to have been declined.

Earlier this month, the 'Single Ladies' hitmaker was spotted out and about for the first time since giving birth on January 7.

Beyonce's mother Tina Knowles recently revealed Blue is "doing great" and she is loving being a grandma.

She said: "She's doing great. She's beautiful. [Being a grandma is] amazing. It's the second best job I've ever had."