He added another title to his name this season in Stockholm, made the final in Basel, losing to Federer in the decider, and reached three further semifinals including Delray Beach, the US Open and the Shanghai Rolex Masters.
The 29-year-old is one of the most loved players on tour and relishes the big stage. His run at this year's US Open captivated New York, as did his silver medal run at last year's Rio Olympics, where he beat world No 1 Novak Djokovic in the first round and Nadal in the semifinals. He carried on this form to lead Argentina to Davis Cup glory.
"This is huge for us to secure Juan Martin. He's a true entertainer and one of the biggest names in tennis. Fans flock to watch him and I can't wait to see him on centre court at the ASB Tennis Arena," said tournament director Karl Budge.
Del Potro said he was eager to return to Auckland.
"I have great memories from winning there in 2009," said del Potro. "I had a late start this year after bringing the Davis Cup title to Argentina, so I am excited to start the 2018 season on a strong and healthy note. It will be the only tournament I play before Melbourne, so it is very important for me and my preparation."
Del Potro will join fellow former champions Jack Sock, John Isner, Roberto Bautista-Agut and David Ferrer in Auckland next year.
"I think this is the best field I've put together," said Budge. "There are five former champions, genuine Grand Slam contenders and the most exciting wave of tomorrow's stars."
The full field for January's event will be confirmed tomorrow.