LAUSANNE, Switzerland (CMC) — Usain Bolt and Yohan Blake are among Caribbean athletes headlining a star-studded cast of Olympic medallists arriving here for today's Diamond league event.

Bolt and Blake are not competing against each other but their participation along with Caribbean and American rivals fresh from the Olympics have heightened expectations at the Pontaise Stadium.

The two Jamaican sprinters are set to clash with athletes who only just over a week ago tried to out run them in London.

Bolt, gold medallist in the Olympic 100 and 200 metres, will attempt to maintain his dominance over the 200 metres when he faces country man Warren Weir, Wallace Spearmon, Churandy Martina and Jason Young.

Blake, the Olympic silver medallist over the 100 and 200 metres is among six London finalists in the 100m which will include the American Tyson Gay.

The 2004 Olympic champion Justin Gatlin was due to compete in this race, but pulled out after suffering from a stomach upset and a fever which saw him hospitalised in Austria. He was scheduled to perform at Monday's track meeting in Linz, but didn't do so as a result of the ailment.

Gatlin has decided to return to the United States for testing, thereby effectively ending his season.

The prospect of a mouth-watering clash in the women's 100 metres also looms as it features a reunion of the top three finishers from the Olympic final in Shelly Ann Fraser-Pryce, Carmelita Jeter and Veronica Campbell Brown.

But similar to the 100-metre male event, the women's 100 is expected to be a continuation of the ongoing contest between Jamaica and the United States for world domination in sprint.

In the 400m, Olympic champion Kirani James will face the London medallists Luguelín Santos and Lalonde Gordon.

Today's race will be James' second for the week after comfortably winning the 400 metres in the Austrian City of Linz on Monday.

Meantime, the Jamaican hurdler and Olympic bronze medallist Hansle Parchment will once again take on American rivals Aries Merritt and Jason Richardson in the 110-metre event.

Merritt and Richardson captured gold and silver in London and the rematch with Parchment in Lausanne is expected to be an interesting face-off.

Caribbean athletes are among 19 London Olympic champions — both individual and relay — and a total of 53 Olympic medallists who have entered for Athletissima 2012, the 11th stop of the Samsung Diamond League.