The highly decorated duo have confirmed their participation in the full-field Asian Tour event and will go head-to-head with the region's top stars including Asia's first Major champions Y.E. Yang of Korea and three-time Asian Tour number one Thongchai Jaidee of Thailand.
Els, nicknamed the "Big Easy" for his languid golf swing and easy-going nature, has claimed more than 60 victories worldwide including two U.S. Open titles, two British Open victories and a record seven World Match Play titles.
The towering South African, who stands at six feet three inches tall, is also one of the most successful golfers in the history of the game. He enjoyed a stellar season in 2012 where he came from behind to win the British Open and also finished ninth in the U.S. Open. He was also runner-up at the WGC-HSBC Champions in China.
"I am delighted to be playing in the inaugural Chiangmai Golf Classic presented by PTT at the stunning Alpine Golf Resort in Chiangmai," said Els.
"I've had great experiences when visiting the Kingdom of Thailand in the past and I have especially enjoyed the warm hospitality of the Thai people and their wonderful cuisine. I really encourage all the golf fans to support the event and experience live all the highly talented players on show.
"This is a landmark moment for golf in northern Thailand and I am proud to be a part of it. I look forward to seeing you all at the end of March.
"It's still the early part of the season and it would be great to get a good result as that will give me great confidence for the year ahead. I'll be flying into the Chiangmai Golf Classic with every intention of winning although it will not be easy against a strong Asian Tour field," added the world number 24, whose appearance in Chiangmai will be part of the Asian Tour's milestone 10th season celebration in 2013.
Campbell of New Zealand, meanwhile, is enjoying a resurgence in form after he put up several strong performances, particularly in the second half of last year. He enjoyed his highest finish since the beginning of 2008 with a third place result in Portugal and was also tied eighth in Hong Kong.
With 2013 marking the start of his 20th year as a professional, Campbell will be eager to add another win to his illustrious career which has seen him achieve eight European Tour wins, three Challenge Tour titles and a U.S. Open triumph in 2005.
Campbell commented: "I am really looking forward to playing at The Alpine Golf Resort in Changmai. I hear that the layout of the course is fantastic and is set within a valley surrounded by hills. It is the first major golf event to be staged in Northern Thailand and the field will include many of the stars from the Asian Tour, which is gaining strength every year, so I encourage spectators to come and watch what should be a very enjoyable tournament and a great experience."