Alonso, returning for his second stint at the Woking team in 2015, will also be behind the wheel on day three of the four-day test, with team mate Jenson Button handling driving duties on days two and four.
McLaren, who will launch their new car online on January 29, have tested Honda’s new V6 Hybrid engine once previously, in an interim car at Abu Dhabi last November. Running was severely restricted on that occasion, so the team will be keen to accumulate as much mileage as possible in the opening Spanish session.