Rosberg joins Speed at Silverstone F1 test.

The GP2 Series' contribution to Formula One continues this week, beyond the excitement recent rounds have brought to the post-qualifying and pre-race slots on grand prix weekends.

After the back-to-back races at Monaco and the N?rburgring, the GP2 teams have a break in their schedule until the next European round at Magny-Cours, and a group test aside, the drivers will be free to occupy themselves for the next month. Two, however, will be on F1 duty this week, with Nico Rosberg having been confirmed as joining Scott Speed for the pre-Canada test at Silverstone this week.

Speed has already been confirmed by Red Bull Racing, and is due to kick off the team's programme today [Wednesday]. The American, however, has a personal goal in mind, as well as helping RBR to prepare for Montreal and Indianapolis, as the carrot of an outing in the team's third car has been dangled in front of him should testing go to plan. Speed would replace Vitantonio Liuzzi for at least one of the rounds - most likely the USGP - but could be offered a chance at both transatlantic outings.

Rosberg, meanwhile, will line-up alongside both Nick Heidfeld and Mark Webber during the week, as Williams and BMW seek to prolong their recent run of podium finishes. The German was recently confirmed as the team's official development driver - a role he shares with Antonio Pizzonia - and has already impressed with his feedback at a previous test.