Double Formula 1 world champion Fernando Alonso will sample a 2018-spec Indycar for the first time next week in a private test, McLaren has confirmed.
As revealed by Autosport, McLaren and IndyCar are currently working together on a plan for the F1 team to join the American series next year with Alonso.
Following Alonso's announcement that he will step away from F1 at the end of 2018, Alonso was linked with a test drive of an '18 Indycar - which the Spaniard admitted was an option.
The team has now confirmed that Alonso will drive in a test which will be closed to the media and the public, but did not outline any more detail.
With IndyCar racing at Portland this weekend, Alonso had been expected to drive at Barber on September 5 in an Andretti-run test.
Alonso's only previous experience of IndyCar came in the 2017 Indianapolis 500, driving what was then a manufacturer aerokit-equipped car in its final year before the series switched to the lower downforce '18 bodywork.
McLaren has been linked to an affiliation with Andretti for its potential 2019 programme, reviving its '17 Indy 500 partnership, as well as a takeover of the financially struggling Harding Racing.
While Autosport understands McLaren is likely to sign a deal with Chevrolet for an engine supply, Honda has stated its interest in working with Alonso once again.