Nelson Piquet and Nico Rosberg, both sons of former world champions, have been given a second Formula One test by Williams.
The duo will help the BMW-powered team in their pre-season preparations. Rosberg will test at Barcelona's Circuit de Catalunya next week while Piquet will be at the Spanish track in the first week of February.
They will use modified versions of last year's car.
Rosberg, son of Keke who became the first Finn to win the world title with Williams in 1982, and Brazilian Piquet, whose father, also called Nelson, won the championship three times - once with Williams - both had initial tests before Christmas.