American singer Beyonce Knowles is having a busy few months. She’s been touring the globe on her “I Am…” tour. Recently, the 28-year-old star and her 23-year-old sister Solange made a whirlwind visit to Tokyo for a special appearance at the Summer Sonic 2009 rock festival in Chiba, as well as to promote Japanese luxury brand designer Samantha Thavasa’s handbags.

Beyonce had two movies to promote, as well — “Cadillac Records” and the Oct 7 DVD release of “Obsessed.” The singer can also be currently seen bouncing about in a Japanese TV and poster ad campaign for Crystal Geyser bottled water. To top everything off, the sisters even got to experience their first earthquake while in Tokyo.

At a brief talk show event, Beyonce said she and her sister had a very laid-back time in between work in Japan. “Actually, we had slumber parties every night – me, my sister and her son. We’ve all been sleeping in the same bed, waking up, watching cartoons that we wish we could understand. We’ve been going crazy over anime and sumo videos. It’s been a really beautiful experience this trip.” That is, until the earthquake struck early in the morning. The word quickly got out on Twitter that Solange slept through it. “My sister said she was scared out of her mind and calling my mom and I was snoring,” Solange wrote. “How did I sleep through a SERIOUS earthquake?”

After that, it was back to business. Beyonce, who has been the face for Samantha Thavasa for a few years, dutifully praised the new collection which has been made in collaboration with Disney. “I like that the bags have a cool rock ’n’ roll vibe to them with their metallic and studded exterior, and a cute design with Mickey Mouse and ribbon motifs, which provide them with a really playful and sexy contrast. They are so kawaii,” she gushed.

Turning to movies, Beyonce said she was proud of her film “Cadillac Records,” in which she portrays legendary American blues, soul, R&B, gospel and jazz singer Etta James. The relationship between the two singers has been a rocky one. Last year, when she got the role, Beyonce said she was honored to be able to play James. The 71-year-old James, for her part, said: “It’s a privilege and an honor to have somebody like that girl. I don’t think she looks like me, but that’s all right. They can fix that up.”

Things turned bad in January when Beyonce sang James’ famous song “At Last” at an inaugural ball for President Barack Obama. James responded at a concert by saying she couldn’t stand Beyonce and that she was “gonna whup” her. “She has no business up there, singing up there on a big ol’ president day, gonna be singing my song that I’ve been singing forever,” James said in an outburst that has become fodder for bloggers ever since.

Meanwhile, Beyonce said she is looking forward to returning to Japan in October for five concerts as part of her world tour. She gave Japanese fans a taste of what to expect by appearing on a TV variety show and singing her new ballad “If I Were a Boy.”

By the way, the Knowles sisters weren’t the only American celebrities to shake, rattle and roll during the Aug 11 earthquake. Singer-actress Jessica Simpson, 29, was in Japan that day to film her new reality TV show “The Price of Beauty.” She wrote on her Twitter page: “Thought I was hallucinating. I have never felt anything like this in my life. Laying in bed watching CNN.”