Kiyou Shimizu has supported the campaign ©Getty Images

Japanese karate star Kiyou Shimizu has joined a campaign to send words of encouragement following the postponement of the Tokyo 2020 Olympics until next year.

She is among athletes whose preparations for their home Games have been hit by the COVID-19 pandemic.

Launched by the Japanese Olympic Committee last week, the campaign hopes to inspire people during the current crisis.

Japan has already been heavily affected by the pandemic with the decision to move the Olympics and Paralympics to 2021 unprecedented.

Among those athletes who have expressed their gratitude is Kiyou Shimizu, the world's leading karateka who will represent Japan at Tokyo 2020.

Karate is due to make its Olympic debut in Tokyo and Shimizu will be a big home hope for gold as a double world champion in the women's kata.

"We, athletes, can't do anything to help on-site," she said.

"But with heartfelt thanks, we will do our best and do what we can."

Table tennis player Tomokazu Harimoto, who is set to make his Olympic debut in 2021, also showed his appreciation for the healthcare workers in his nation and hoped that the situation could unite people.

Tennis star Kei Nishikori shared his healthy breakfast tips, featuring fruits such as kiwi and apples and how to make a morning smoothie.

Kakeru Tanigawa, Japan's youngest national artistic gymnastics champion, showed some of his exercises that people can do from home.