Viljoen back in New York
South African javelin throw record holder Sunette Viljoen will return to her favourite hunting ground, while former world champion Mbulaeni Mulaudzi makes a comeback at Saturday's Diamond League meeting in New York.
The duo will lead a four-member South African contingent in the third leg of the global series, which also includes national 400m hurdles champion Cornel Fredericks and rising one-lap sprinter Wayde van Niekerk.
While Viljoen has not yet reached her best form this season, she will hope for a repeat performance of last year's New York meeting, where she improved her own South African record with a heave of 69.35 metres, placing her sixth on the all-time list.
Viljoen's best throw this year was the 61.87m effort which gave her the national title in Stellenbosch last month.
The 29-year-old South African, who was fourth at last year's London Olympics, will come up against an old foe in the form of Russia's Mariya Abakumova, the defending world champion.
Abakumova boasts the leading throw in the world this year of 69.34m, while Olympic silver medallist Christina Obergfoll of Germany has dropped the javelin at 64.53m this season.
Viljoen, however, will not be intimidated by their early form, as she is known to be a late bloomer and should be at her best later in the season.
She will hope to reach the world championships qualifying standard of 62 metres.
Meanwhile, Mulaudzi will make his first appearance on the track in the 800 metres this season after he missed last year's Olympic Games due to injury.
The veteran middle-distance runner could not have asked for a tougher assignment as he prepares to line up against world record holder David Rudisha.
Rudisha again displayed at the Doha Diamond League meeting earlier this month that he will be difficult to beat this year, setting a world leading time of one minute, 43.87 seconds (1:43.87).
Olympic bronze medallist Timothy Kitum of Kenya will also toe the line.
Fredericks will be relishing a rematch with American Michael Tinsley, the Olympic silver medalist, who won a tight finish in 48.92 seconds in Doha.
The South African finished third in that race in 49.35 after leading most of the way. He was only passed by Tinsley and fellow-American Bershawn Jackson after the final hurdle.
Johnny Dutch of the United States, who has run the fastest time over the barriers this season (48.02), and Puerto Rico's Javier Culson will also be in the race.
Fredericks boasts the fourth fastest time in the world this year after clocking 48.78 at the national championships.
South African 400m champion Van Niekerk will be in action in his first major international meeting.
The 20-year-old ran a time of 45.42 seconds at a Varsity Athletics meeting in Johannesburg last month, narrowly missing the world championships qualifying standard of 45.28.
However, his progression this season suggests it is only a matter of time before he books his place in the team for the global showpiece in Moscow, Russia, in August.