Hello Kitty and Pikachu have been enlisted to give Osaka a boost in its efforts to host the 2025 World Exposition.

"I would like for you to represent Japan and proactively (promote) the attraction of Osaka inside and outside of the country," Foreign Minister Taro Kono said Tuesday in handing out letters to appoint popular feline character Hello Kitty and Pikachu, one of the most famous Pokemon characters, as special ambassadors for the bid.

The characters will be used for pamphlets and gifts promoting the city's bid to hold the expo, with Saclay in the suburbs of Paris, the central Russian city of Yekaterinburg and the Azerbaijan capital Baku the other contenders.

Member nations of Bureau International des Expositions will vote on the host city at the expo governing body's general meeting in November next year.

Soccer star Keisuke Honda and Shinya Yamanaka — a professor at Kyoto University who won the 2012 Nobel Prize in medicine — will also be appointed as special ambassadors to promote the bid, according to the Foreign Ministry.

Osaka last hosted the event in 1970 and Aichi Prefecture was the host in 2005. World expositions are held every five years, with the next one in Dubai in 2020.