MADRID, Feb 4, 2008 (AFP) - Formula One heavyweights Renault signed up Japanese pilot Sakon Yamamoto on Monday to be a test driver.

The 25-year-old has Formula One experience having driven in 14 Grand Prix´ for minnows Super Aguri and Spyker.

"We are happy to welcome Sakon to the heart of the team this year," announced Renault boss Flavio Briatore in a statement.

"We are looking towards an especially aggressive development programme and his experience in Formula One will be very useful for us in this context."

Yamamoto was ecstatic to have joined the team.

"I am very excited to have joined Renault this season," said Yamamoto.

"It is an honour for me to be associated with a team that has won several world titles."

Renault have re-signed two-time world champion Fernando Alonso, who returned just a season after leaving for McLaren where he and rookie Lewis Hamilton failed to gel on a personal level, though both went close to winning the title.

The French team have also recruited Brazilian Nelsinho Piquet, son of former world champion Nelson, and his 23-year-old compatriot Lucas Di Grassi, who is also a test pilot.