Brendon Hartley says it remains "a possibility" that he will race for Porsche's Formula E squad in 2019/20, despite joining Toyota for the World Endurance Championship over the same period.
Hartley has been involved in Porsche's initial on-track development for its ABB FIA FE powertrain alongside Neel Jani, who is already confirmed as one of the manufacturer's drivers for its first season in the electric single-seater championship.
At the first full example of Porsche's manufacturer testing programme ahead of 2019/20 at Calafat - its initial days of private running were spent shaking down its development car at its Weissach base - Hartley said he was "definitely interested" in becoming an FE race driver for the marque.
He has since agreed to join Toyota's LMP1 line-up from next season in place of Fernando Alonso, but Hartley insisted he could still combine those commitments with a Porsche FE drive.
"I would say yes, but I don't know if it's going to happen or not," Hartley said ahead of the official Le Mans test last weekend.
"It's definitely a possibility but I don't have any more answers than that.
"I'm still involved with the development of the Porsche [FE car], I'm actually there next week as part of their testing. Beyond that I don't know.
"The priority for me was signing up for Toyota, having a full-time race seat and being back in Le Mans."
The ex-Toro Rosso Formula 1 driver retains a factory Porsche contract for 2019.