Mercedes will slowly ramp up its collaboration with George Russell ahead of his move to the team at the end of the season, but the Briton's priority remains his commitment to Williams insists Toto Wolff.
Russell will replace Valtteri Bottas at Mercedes next year following a three-year apprenticeship with Williams.
But the 23-year-old's affiliation with the German manufacturer allows Russell and the Brackley squad to start working together even before the end of this year's campaign, but under certain conditions.
"Over the autumn we’re going to slowly but surely collaborate more without ever jeopardising or interfering into the current championship," said Wolff. "But we haven’t started yet.
"We need to respect that George is still a Williams driver and needs to do the utmost for Williams to climb up the ranks in the Constructors’ Championship and he’s done a good job so far.
"And we have Valtteri and Lewis, they are our drivers."
Williams chief executive Jost Capito made clear that Russell's tenure with the British outfit hasn't been impacted by his star driver's upcoming move to Mercedes.
"There is not much involvement of the drivers for next year's development yet," Capito said. "He’s doing his job preparing the races and preparing for the rest of the season."
"There’s nothing changed after the decision that he’s at Mercedes next year."