ADVENTURER Bear Grylls has signed up as an ambassador of an epic tri-services round the world voyage.

The Isle of Wight-born former SAS reservist has thrown his weight behind Exercise TRANSGLOBE, an adventure which will see more than 500 Army, Navy and Air Force personnel take to the seas for a 13-leg circumnavigation on July 11.

He said: "Exercise Transglobe is a challenge of the highest calling - one that stretches human endurance, tests resolve and builds character through one huge adventure.

"I admire all involved and wish them God's speed and safe travels. Thank you for supporting these fantastic HM Forces personnel."

Grylls joins TV presenter Nick Knowles as well as actor Robert Powell and his wife Babs as ambassadors of the event, organised by the Joint Services Adventurous Sail Training Centre based in Gosport.

Each of the Armed Services will be allocated one of the identically equipped JSASTC Challenge 67ft STC and the respective individual Service will be responsible for providing the crew for each of the legs.

Those taking part span all ages and rank and range from senior high ranking service personnel to raw recruits, some of whom only signed up recently.

Everyone onboard will experience the highs and lows of long ocean passages and landfall in some of the most exciting cities in the world.

The route includes two long Southern Ocean legs, the longest of which includes a rounding of Cape Horn.

The year long exercise, which will finish back in Gosport on June 26, 2010, will include participation in the Sydney to Hobart Race in December and the Antigua Race week in April 2010.