A new stamp marking the 100th Liffey Swim is set to go on sale this week.

An Post's latest offering will feature an image of the Jack B Yeats painting showing the iconic Dublin swimming event.

Yeats' 'The Liffey Swim' is an Olympic medal winning work, as the painter took him the silver medal in the art competition at the 1924 Olympic Games for his work.

In a statement, An Post said: "What better way to celebrate a century of the famous Liffey swim than with an Olympian effort that is one of the great iconic images of this famous event."

It comes as competitors prepare to take part in the 100th Liffey Swim this coming Saturday.

While it takes place in the river that runs through Dublin city centre, the event is officially classed as an open sea event due to the impact of the sea tide and the fact that participants are swimming in salt water.

The first sea swim, organised by engineer Bernard Fagan, took place on July 22nd 1920 and had 27 participants.

This year's event will see hundreds of people swimming 2,200 metres downstream - passing under a dozen bridges in the process.

The An Post Liffey Swim stamp, meanwhile, goes on sale from tomorrow August 1st.