Amuro to Boku(2020)

Amuro to Boku

In 1981, Osamu was obsessed with the popular "Gundam" series. One day, he stealthily takes his older brother's Gundam plastic models and, while playing with them, hears a mysterious voice call out to him. The person in question was Amuro Ray himself who appeared as he was in the anime...!??

(Source: Kadokawa, translated)