But the Republic of Ireland international departs Arne Slot’s side after voicing his ambitions to pursue more frequent first-team opportunities elsewhere.
His switch to west London coincides with a summer of changes for the Premier League champions with multiple transfers in and out anticipated.
Giorgi Mamardashvili will arrive from Valencia as Alisson’s new understudy while Liverpool are expected to add to Jeremie Frimpong’s recent capture.
Kelleher is Liverpool’s second first-team departure following Trent Alexander-Arnold’s move to Real Madrid and could be joined by several others.
The 26-year-old joins the Bees on an initial £12 million with the deal potentially rising to £18M as Mark Flekken’s direct replacement.
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