Rory McIlroy will be keeping a promise to fellow major champion Ernie Els when he lines up in the South African Open this week as the European Tour begins a new calendar year.

Els is player-host of the second oldest national Open championship in world golf and extracted the commitment when he played in the 2014 Irish Open, which is hosted by McIlroy’s Foundation.

“Rory was very serious about coming to South Africa when I told him he ‘owed me one’ at the Irish Open,” said Els.

“He’ll be the man to beat. Rory is by far the class player in the field when you look at the world rankings,’ he told reporters as golfers tested out the course at Glendower Country Club before Thursday’s start.

“He’s the guy everyone will be looking up at to beat. There’s so much excitement among everyone that he’s here.”

The 27-year-old McIlroy, ranked second in the world, played the tournament once before in 2008, not long after turning professional, and shared third spot with Els.

Nick Faldo, now 59, makes a return to the Tour after a lay-off of more than two years.

But South Africa’s three top ranked golfers -- Branden Grace, Charl Schwartzel and Louis Oosthuizen -- have all elected to skip the event.

“Naturally I’m disappointed they are not here, I think we all are. I think they still want to spend more time with their families and I understand that," Els added.

"But I hope we can persuade them to play next year because the spectators are crazy about them and want to see them play."