Ana Ivanovic is confirmed in a star-filled field for January's ASB women's Classic.

The 2014 champion joins fellow former world number ones Venus Williams and Caroline Wozniacki in the line-up for the tournament in Auckland.

Two-time grand slam winner Svetlana Kuznetsova and young American Sloane Stephens are also returning.

While the 2010 field had five top 20 players, in Williams, Wozniacki and Ivanovic, Auckland has attracted three of the biggest names in women's tennis.

The cut off for direct acceptance is 77, making it one of the strongest ever.