She'll be one of the top contenders in January's ASB Classic, alongside top seed Caroline Wozniacki, former Wimbledon finalist Agnieszka Radwanska and Auckland veteran Julia Goerges.
"Vika was always someone we wanted to bring to Auckland," said tournament director Karl Budge. "Along with Serena, she has been the best player in women's tennis over the last six or seven years and is a genuine top two or three player."
For her part, the Belarusian believes coming to Auckland is the ideal place to begin her return to full time tennis.
"I am looking forward to getting back on the court to compete in January and I can't think of a better place to start the 2018 season than in Auckland," said Azarenka. "I've worked extremely hard with my team over the last few months and continue to do so for the new season and with my goal in mind to get back to world number one and compete for Grand Slam titles. My expectations remain high as always."
Azarenka has played in Auckland once before, losing in the second round in 2006.
"I haven't been to Auckland for a long time and everyone says such wonderful things about the tournament and the city," said Azarenka. "I am really excited to experience it and be back".
Williams is more of a long shot, especially after her less than perfect experience in 2017, where she lost in the second round to unheralded compatriot Madison Brengle and struggled in the windy conditions. But Budge has offered a wildcard to the Williams camp, ahead of her anticipated comeback at the 2018 Australian Open following the birth of her daughter Alexis in September.
"I've said I will save her a wildcard," said Budge. "If she needs some match play before Melbourne, then we will be in the perfect position to offer that."
German Goerges, who will make her 9th ASB Classic appearance in 2018, will come to Auckland in great form. Across this year she has won two titles (Moscow, Zhuhai) and reached three other finals (Mallorca, Bucharest, Washington DC) to reach a career high ranking of No14.
World No 23 Barbora Strycova and 2016 Olympic champion Monica Puig are other notable inclusions in the full field revealed on Wednesday.
Full list of main draw players for the 2018 Women's Classic:
1) Caroline Wozniacki (3)
2) Julia Goerges (14)
3) Barbora Strycova (23)
4) Agnieszka Radwanska (28)
5) Mona Barthel (48)
6) Lauren Davis (50)
7) Yulia Putintseva (52)
8) Donna Vekic (55)
9) Monica Puig (58)
10) Varvara Lepchenko (63)
11) Christina McHale (64)
12) Marketa Vondrousova (67)
13) Maia Haddad (71)
14) Kirsten Flipkens (74)
15) Veronica Cepede Royg (75)
16) Alison Van Uytvanck (76)
17) Johanna Larsson (80)
18) Su-Wei Hsieh (82)
19) Madison Brengle (83)
20) Lara Arruabarrena (84)
21) Petra Martic (89)
22) Taylor Townsend (94)
23) Nao Hibino (97)
24) Polona Hercog (101)