On December 12, 2012, the Kurdish National Council of Syria issued a statement announcing its decision to join  the Syrian National Coalition of Revolutionary and Opposition Forces as a member “on behalf of the Supreme Kurdish Council of Syria”. The decision was made with the approval of the Kurdish Democratic Union Party (PYD—sometimes referred to as the People’s Council of Western Kurdistan)  also a member of the Supreme Kurdish Council.  

The KNC/Supreme Kurdish Council announcement represented a significant development in the Kurdish attitude toward the opposition -- it helps to fulfill the stated goal of greater minority representation in the new coalition and  it represents an apparent shift in the position of the PYD which had rejected the creation of the National Coalition soon after its announcement on November 18, 2012. 
Below is a translation of the statement; the original, in Arabic, can be found here.

The Executive Committee of the Kurdish National Council in Syria:

A Statement on Joining the National Coalition of Syrian Opposition Forces

On December 9–11, the executive body of the Kurdish National Council (KNC) met to discuss topics on its agenda and adopted a number of resolutions relating to its work in political and organizational areas:

1. The meeting emphasized that the Kurdish movement in Syria is an essential part of the Syrian revolution to overthrow the authoritarian regime and that it stands with all the forces of the Syrian people in their demands for freedom and dignity.
2. The meeting unanimously re-endorsed the documents resulting from the meeting held in Hawler on November 23, 2012, between the People’s Council of Western Kurdistan and the KNC about implementing the agreements and participants agreed on a common political vision.
3. The meeting called for the need to unify the efforts of the Syrian national opposition and noted that the emergence of the National Coalition of Syrian Revolutionary and Opposition Forces to serve the revolution was a positive step in this direction. The meeting also called on the Kurds in Syria to move forward on the basis of a future partnership with the coalition through a recognition of the legitimate national rights  of Kurds by all sides in accordance with the international covenants and conventions.
In this context, the meeting ended with a decision to join the National Coalition on behalf of the Supreme Kurdish Council, which represents all Kurdish groups in Syria. A delegation will be tasked with the authority to implement the decisions of this meeting. 
4. The meeting adopted a decision to set a date for a national Kurdish conference to begin, dependent on the adoption of draft regulations and further political discussion.
Long live the revolution of Syrian people
And victory to the cause of the Syrian people
The Executive Body
The Kurdish National Council of Syria