2016 men's ASB Classic champion Roberto Bautista-Agut will be returning to defend his title.
The world No 17 backed up his Auckland success with a second ATP World Tour title for the season in Sofia, Bulgaria, and has twice reached the round of 16 at Grand Slams this year - at the Australian Open and Roland Garros, where he took a set off world No 1 Novak Djokovic.
Bautista-Agut captured the Auckland crown off the back of a stunning week which saw him beat two former champions (Jiri Vesely, 2014 and John Isner 2012 & 2015) as well as World Number 10, Jo-Wilfried Tsonga en route to lifting the trophy.
A solid showing at the Rio Olympics earnt him a spot in the quarter finals, going down to eventual silver medallist Juan-Martin Del Potro whilst he was runner-up at Winston Salem last week - the final tune-up event prior to this week's US Open.