Pop star Hikaru Utada, one of Japan's best-selling artists of all time, is calling it quits at the end of the year, but not before performing for fans this week in a concert that will be streamed live online.

The New York-born singer-songwriter shocked fans when she announced on her blog in August that she would be taking a hiatus starting in 2011 to focus on self-improvement. She hasn't said if the break is permanent or temporary.

She will perform to sold-out crowds Wednesday and Thursday in Yokohama. The Wednesday show will be simulcast at 64 movie theaters around Japan.

Video streaming provider Ustream Inc. said Monday the Wednesday concert would also be shown live online, accessible to viewers globally.

Utada, 27, has said that her life has been devoted to music since she was 15 and now it's time to shift focus.

"I want to study new things, and see and experience things in this big world that I don't know about," she wrote on her blog.

Utada shot to fame when her debut album "First Love" was released in 1999. The album — Japan's best-selling album ever — sold more than 8.5 million copies and millions more across Asia. Her subsequent albums also became smash hits.

She won fans across Asia for her mix of American pop, R&B and hip-hop.

Her forays into the U.S. market have been less successful. She released her North American English-language debut album "Exodus" in 2004 and another album "This is It" in 2009.

Utada grew up in both New York and Tokyo.