The 25-year-old has been a Superstock 1000 frontrunner for the past two seasons, and was previously a champion in Australian Superstock and Superbikes.
Staring also made wildcard appearances in his home round of the Superbike World Championship for his Superstock squad Pedercini for the past two years.
His Gresini deal marks his return to the grand prix paddock eight years after a one-off 125cc appearance at Phillip Island.
"Racing in the MotoGP class has always seemed very remote, practically unattainable," said Staring.
"Now that I have a real chance to race in this championship with Go and Fun Honda Gresini, it is almost unbelievable - a dream come true.
"It's the greatest opportunity of my career and I will be giving it my best."
Michele Pirro rode Gresini's FTR-Honda CRT bike this season, finishing a shock fifth overall in the season finale at Valencia before leaving to become Ducati's test rider.
Gresini has retained Alvaro Bautista for its lead Honda effort.
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