McLaren say the appointment showcases the collaboration that exists between the team and engine partners Honda to discover, train and give opportunity to young and promising racing drivers.
Matsushita won the All-Japan Formula Three Championship in 2014 before graduating to GP2 for 2015 - racing for ART Grand Prix, alongside eventual champion Vandoorne.
“This season I am ecstatic to be joining the McLaren-Honda F1 team as a test and development driver,” said Matsushita, who will again contest the GP2 Series with ART this year.
“To step into the world of Formula One fulfils a boyhood dream, and is a huge step forward in my career. I will do the utmost to help the race team on the track, by gathering data to feed back into the development and set-up of the car through simulator work.
“Last year’s GP2 Series season was a steep learning curve for me. It was my first year racing in Europe - but, thankfully, my experiences with Honda’s young driver programme meant I was well prepared for the task ahead.
“As a GP2 Series driver, my sole focus for 2016 is to win the championship. I believe that I have the best package around me to succeed and reach my ultimate goal of becoming a Formula One driver.”
McLaren’s racing director Eric Boullier added: “Nobu’s first season racing in Europe showed great promise - he produced some extremely impressive performances, and with experience and consistency, will surely build on that potential in 2016.
“His position as a McLaren-Honda test and development driver will be extremely important - he’ll underline and corroborate the learning we acquire at the track, and will play a key role in improving our performance throughout 2016.”
McLaren will unveil their Honda-powered 2016 car, the MP4-31, on Sunday.