The BBC One comedy-drama - which returns in early 2013 - stars Ben Miller as DI Richard Poole, a stuffy English detective who is relocated to an idyllic Caribbean island.
Davis, Spearritt and Gavin & Stacey's Mathew Horne will all appear in the second series, alongside James Fleet (The Vicar of Dibley), Lucien Laviscount (Waterloo Road), Neil Pearson (Drop the Dead Donkey), Ralf Little (The Royle Family) and Shaun Parkes (Human Traffic).
"It's great to be working with such a fantastic cast against the beautiful backdrop of Guadeloupe," said Davis. "Being filmed on location really offers a sense of authenticity and adds to the quirky comedy, so it's been brilliant to experience first-hand."
The guest cast also includes James Murray (Primeval), Sean Pertwee (Dog Soldiers), Cherie Lunghi (Excalibur), Dexter Fletcher (Hotel Babylon), Stephanie Beacham (Dynasty), Gemma Jones (Spooks) and singer Jamelia.
Death in Paradise star Ben Miller previously told Digital Spy that he was happy to work with Jamelia, calling the musician "a very talented actor".
"She did a great job and I'm sure it'll be the beginning of big things for her," he said.
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Watch a clip from the first series of Death in Paradise below: