There are at least three AK. One is the British girl group,Atomic Kitten.
In Taiwan's album, we used AK as a shortened name.
Member are Liz McClarnon, Natasha Hamilton ,and Jenny Frost.
The group has changed member for twice.
After they released their Greatest hits, they also made both only Asian and British released collection album.
Natasha also started her solo career.
The other one is a Japanese singer-songwriter,Kakihara Akemi(柿原 朱美). AK is from her name's first and second letter.