Beyonce and Jay-Z have reportedly revealed the names of their newborn twins - Sir and Rumi.

Celebrity news site TMZ first reported the couple have trademarked the name for their new twins, believed to be a son and daughter.

It has now been confirmed by Sky News who say the couple have filed to US authorities to copyright 'Rumi Carter' and 'Sir Carter' to make sure no one else can profit from the names.

Although the pop superstar and the rapper have yet to comment on the matter themselves, the claims were submitted from an identical California address to an earlier application for the name of their five-year-old daughter, Blue Ivy Carter.

The 35-year-old star, whose 2016 album Lemonade narrowly missed out on a Grammy, announced she was pregnant in February. She posted an image showing her bump on Instagram.

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“We would like to share our love and happiness. We have been blessed two times over. We are incredibly grateful that our family will be growing by two, and we thank you for your well wishes. The Carters,” she wrote at the time.

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TMZ said that the names were revealed in trademark documents filed to the United States Patent and Trademark Office on Monday. Rumi is celebrated as the name of a Persian poet, born in 1207.

Beyoncé and Jay-Z’s company has filed papers to trademark the names for everything from fragrances and cosmetics to baby gear, tote bags and water bottles, TMZ said. Jay-Z's real name is Shawn Carter.