The pop-up, which is being held at the group’s new restaurant - which opened last month - will run for six weeks from 1 September to 8 October and will see a range of Hello Kitty inspired items make it onto the menu.
The sushi bowl and green tea specialist is creating dishes that will include a Hello Kitty poké bowl, ice cream sundaes, cupcakes and other desserts linked to the white Japanese Bobtail cat character.
A range of teas has also been created, including ceremonial grade matcha tins, matcha latte mix, and new flavour Kukicha green tea infused with yuzu.
And for those Hello Kitty fans merchandise will also be on offer including Hello Kitty tote bags, postcards and posters.
It's not the first time the iconic cartoon character has been adopted by the restaurant industry. Last year Soho bakery Cutter & Squidge ran a Hello Kitty Secret Garden pop-up for three months.
As well as its Fitzrovia restaurant, Tombo operates two other London sites, in South Kensington and Soho. Both sites will also offer a range of Hello Kitty merchandise as well as a small selection of the limited-edition menu items during the lifespan of the pop up.
The Japanese character Hello Kitty was born in 1974 and has become a global phenomenon spawning a range of merchandise, cafes and even her own aeroplane.