"From my first laps in F3 I really enjoyed the car - after this December I hope to understand it well so we can hit the ground running in 2018."
Armstrong, who will return to New Zealand over summer to compete in the Toyota Racing Series, has already had a couple of tests in Formula 3 and put up some very impressive laps.
"Marcus really put up a brilliant display in his first full-time season in European single-seaters and I can't wait to see him back on track in F3," Prema boss Rene Rosin said.
"He will need to step up for such a challenging series but I'm confident he will be absolutely up for it, considering how impressive he was this season and how he kept up with his professional improvement.
"Our F3 line-up is coming together nicely and we are looking forward to the winter with confidence."