ERNIE Els, Lee Westwood and Martin Kaymer will join Rory McIlroy to make it a quartet of former World Number Ones at this week’s BMW PGA Championship, the first of eight Rolex Series events on the European Tour in 2018.

South African Els was the first of the four to reach the summit when he overtook Tiger Woods in 1997, before holding the coveted position twice more in 1998.

The World Golf Hall of Fame Member will be making his 22nd appearance at the BMW PGA Championship when he tees it up this year, and he has an impressive record at Wentworth, having won the former World Match Play on seven occasions.

The four-time major champion was also instrumental in the extensive renovation of the West Course ahead of last year’s BMW PGA Championship, working closely with an advisory team which included Thomas Bjørn, Paul McGinley and David Jones on the successful programme of improvements.

In a similar fashion to Els, England’s Westwood reached the pinnacle of the sport by knocking off the dominant Woods. In ascending to the top position in 2010, Westwood ended Woods’ streak of 281 consecutive weeks as World Number One.

Westwood, who will be making his 25th consecutive appearance at the BMW PGA Championship this year, finishing runner-up on two occasions, sat at the top of the rankings for more than four months before he was overtaken by Kaymer in February 2011.

Kaymer’s own rise to the top came the year after he won the first of his two majors – the 2010 US PGA Championship.