Up to 75,000 runners will be limbering up for Sydney's 39th City2Surf race this morning.
Heather Turland, who won the event in 1994 and 1996, is putting in a star appearance almost a decade after retiring from competitive running.
She will be joined by her 21-year-old son Cade.
Other high-calibre runners include Andrew Lloyd, winner of the City2Surf in 1983, 1984, 1986 and 1993.
Queenslander Michael Shelly, who finished just 13 seconds behind Martin Dent last year, is determined to crack the 2008 winner's 41:07 this time round.
While former world champion marathon man Robert de Castella will not be joining in, his humble brother-in-law Anthony Walsh, 49, will.
Describing himself as "not a particularly competitive runner", Mr Walsh, who lives in Melbourne, has no intention of emulating de Castella's 1981 City2Surf-winning time of 45.47.
"I'm expecting to do about 65 minutes," he said.
The Ambulance Service of NSW says runners should wear sensible clothing and footwear for the race, including a hat, sunglasses and sunscreen.
Dehydration can be avoided by drinking plenty of water.
Symptoms such as chest pain or severe shortness of breath should not be ignored – if they occur, entrants should stop and seek medical attention.
Anyone with influenza-like symptoms, including fever, chills, a sore throat or cough, should not enter the race.
The RTA advises runners to leave their cars at home. Roads will be closed in the Sydney CBD, Darlinghurst, Kings Cross, Edgecliff, Bellevue Hill, Rose Bay, Double Bay, Vaucluse and Bondi.
The Eastern Distributor northbound off-ramp to William Street and southbound off-ramp to Palmer Street will also be closed.
The Cross City Tunnel will be closed to eastbound traffic between Harbour Street and Bayswater Road, but will remain open to westbound motorists during the event.
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