Rossi is one of the best riders in the world on two wheels
Six-time MotoGP world champion Valentino Rossi will switch from two wheels to four next month when he drives in the Wales Rally GB.
The 29-year-old will race in a Ford Focus which will carry logos in support of the BBC's Children in Need appeal.
Rossi, who is said to be interested in a long-term switch to rallying, first raced in the Welsh Rally back in 2002.
"I am hoping for a good result at next weekend's Monza Rally to prepare for the forests of Wales," said Rossi.
"I'm also delighted to be supporting BBC Children in Need, which does such vital work in the UK.
"It's a great charity and one I'm very pleased to be involved in."
The charity will hold a charity auction on Friday 5 December, as well as collecting money over the course of the action.
"It's a tremendous honour to have Valentino Rossi promoting the charity," said Children in Need spokesman Marc Phillips.
"We have had a remarkable response to this year's event on 14 November - and this will be a fabulous final flourish for us."
Rossi made his World Rally debut in Wales in 2002 but crashed out on the second stage, while he finished 11th in the 2006 Rally New Zealand.
He has also competed in the last three Monza Rally races, winning the 2006 and 2007 events.
Rossi's first foray into the WRC was at the Wales event in 2002
Rossi has also been linked with a move to Formula One recently having tested for Ferrari, but he has signed a two-year contract to keep him at Yamaha until 2010.
Wales Rally organiser Andrew Coe added: "He is a supreme ambassador for all forms of motorsport, as well as a remarkably-gifted sportsman.
"We look forward to seeing him take on the challenges of the Welsh forests."
Rossi's co-driver in Wales will be his 48-year-old compatriot Carlo Cassina, with the event starting on 4 December and running for four days.