Cunningham’s deal is a season long dual registration and he was surprisingly unveiled to Dons’ fans and supporters at their meet the player’s event at Doncaster Dome last Friday night.
The East Hull born 22 year-old is the eldest of the Cunningham brothers at the KC Stadium and made his first team debut for the Airlie Birds in 2010 in an away fixture against Catalans Dragons in Super League.
Dons’ head coach Tony Miller said: “This is a fantastic signing for the Dons and our squad is looking very promising ahead of our National Rail Cup campaign.
“Liam is dangerous with ball in hand; he’s a good defender, has bags of pace and comes with a great reputation from East Yorkshire.
“He’s also extremely versatile and can play in a number of positions including centre, back row or loose forward.
“I’d like to thank the coaching staff at Hull FC for making this dual registration a possibility – I’m sure Liam will be a great asset to the club.”
“I played against Doncaster for Hull FC in last year’s pre-season friendly so I know first-hand what a great venue the Keepmoat Stadium is.
“I spoke to a few lads at training last week and they all said we’ve got a strong squad with a good mixture of youth and experience and we should go well this season.”