It has been reported that Taeyang will be collaborating with the famous Japanese singer Thelma Aoyama on her upcoming album this January, which will totally make sense because Bigbang will have their concert in Japan on February 2010.

Here is the info posted:

Thelma Aoyama x SOL from BIGBANG
Fall in love
Label: Universal Music Japan
Release Date: 2010/01/27
Catalog: UPCH-5640
Price: ￥1,000

Some info about Thelma:

• Very famous R&B singer in Japan, known for her unique voice
• She is famous for her collaboration song with Soulja "Koko ni Iru yo".
  
• Her famous song “Soba ni Iru ne” topped the charts (she made the Guiness World records for 2 million full track downloads of this song)
• Her album released in Feb, was #1 on the Oricon Weekly Charts