The US singer has a huge following in Japan and visited the country three months after the 2011 disaster, declaring "Japan is safe" and calling on tourists from around the world to do the same.

"It seems like yesterday that I was watching the shocking footage of the devastating earthquake and tsunami on the news, and thinking, 'what can I do to help?'" she said in a video posted on Twitter.

"Seeing and hearing about the vast recovery of your beautiful cities, I have so much respect to the people of Japan for your strength, kindness, and love for each other," she said in the clip of just over a minute.

In the video -- viewed 1.5 million times -- the currently lilac-haired star said Japan's response would give hope to people who are "fighting through" the coronavirus pandemic.

"However, I can also imagine that there are still many people fighting through the pain, emotionally and mentally," she said.

"So, let's all continue to support each other, be kind to each other and love each other. I'm always praying for you, Japan, for a better world."

She ended the tribute by saying "aishitemasu", meaning "I love you" in Japanese, and blowing a kiss.

After the 2011 disaster, which left around 18,500 people dead or missing, the performer launched a fundraising drive and took part in a charity concert to support reconstruction efforts.