James Cracknell and Ben Fogle take on bike challenge
Adventurers James Cracknell and Ben Fogle are to tackle a 2,745-mile bike race for their next TV challenge.
The Tour Divide - which stretches from Canada to Mexico - is the world's longest off-road race.
Cracknell and Fogle want to break the course record by completing it in 17 days.
They will be filmed during their preparations and training for the four-part BBC Two series to be screened later this year.
The pair will set off from Banff, Canada, in August, and will have to cover more than 160 miles a day if they want to beat the current record of 17 days and 21 hours.
Neither of the men have had any previous mountain bike training - Olympic rower Cracknell has ridden road bikes but Fogle has rarely cycled at all.
"I love a challenge, but as a cycling novice this is a huge test and could well prove to be the toughest yet," said Fogle.
To beat the world record, they must race unsupported so they will have no back-up team with equipment or supplies.
They will also have to carry everything they need on their bikes, including camera equipment.
The duo have completed other challenges including crossing the Atlantic in a rowing boat for TV series, Through Hell and High Water.
In 2009, they endured a race to the South Pole which formed the series On Thin Ice.
BBC executive producer Lisa Edwards said: "We're delighted that James and Ben are returning to BBC Two with another inspirational challenge which, as their previous series' have done, is sure to keep viewers enthralled."