Ratu Naulago is set to switch codes to sign for Bristol after making a "spectacular" impact in Super League.
The serving soldier has notched 17 tries in 21 appearances for Hull after being spotted playing for the British Army sevens team last year.
The 28-year-old's switch - which will go through once the Super League season finishes - will give him the chance to move back home with his wife after being given a temporary release from active service with the Yorkshire Regiment.
The Fijian-born wing said on Bristol's website: "I'm delighted to have signed for Bristol Bears for the next few seasons.
"They play a really attractive brand of rugby which I think will suit me and get the best out of me as a player.
"Moving to Bristol means my wife and I will be close to family and friends also.
"I would like to thank Hull FC for the opportunity they gave me in professional rugby - I will always be thankful for that. I have loved my time at the club and the fans have made me feel very welcome.
"I hadn't considered playing anywhere else in rugby league. I have too much respect for the club and for what they have done for me, so leaving for another Super League team was never an option.
"I am fully committed to the club for the rest of this season when we do get back playing and I am determined to do my best for the team to finish on a high, it would be fantastic to try and win something with the club.
"I would also like to thank the army for their continued support with my rugby career which I'm extremely grateful for."
Bears director of rugby Pat Lam added: "He is incredibly fit, with great pace and an eye for the try line.
"He's been consistently outstanding in his relatively short time in Super League and that's testament to the great work from the team at Hull FC.
"A lot of people are sitting up and taking notice of his spectacular performances."
We are committed in our support of responsible gambling. Recommended bets are advised to over-18s and we strongly encourage readers to wager only what they can afford to lose.