The Reds were touted with an interest in Kelly in the early days of the summer transfer window, having scouted the 20-year-old on a number of occasions this season.
Kelly was considered as a possible deputy for Andy Robertson ahead of Moreno’s departure at the end of June, as the Spaniard’s contract expires on July 1.
“It’s a fantastic club. The move has come around quite quickly, but I’m happy to be here and can’t wait to start playing,” the youngster said.
“Premier League football is what I’ve always wanted to achieve.
“I want to play as many games as possible and I feel like this is the right place for me to try and do that.”
Kelly’s comments hint at a late move from the Cherries, eager to move ahead of the likes of Liverpool, and also why he may have been against a switch to Anfield.
With Robertson firmly cemented as first-choice left-back, and still just 25, Kelly would have serve as the Scot’s backup which, as Moreno’s paltry five appearances this season prove, may not provide the game time he requires.
It remains to be seen where the Reds will turn, but the popular choice will be to promote under-23s standout Adam Lewis.