Kellett reached the last 16 of the 2007 Winmau World Masters, having beaten Andy Fordham among others on the way to the televised stages. He lost 1-3 in sets to the then BDO world champion Martin Adams.

He also qualified for the 2008 Zuiderduin Masters, losing both of his group games to Mareno Michels and Darryl Fitton.

In 2010, Kellett won both the Scottish Open and the Antwerp Open. His good run of form helped him to qualify for the 2010 Winmau World Masters as the second seed. He knocked out Tony West in the last 16, before defeating Ted Hankey and Martin Phillips (both in sudden-death legs) to reach the final. He lost 3-7 to Adams, who won his third consecutive World Masters title.

Kellett also qualified for the 2011 BDO World Darts Championship, again as the second seed. He defeated two-time semi-finalist and pub team-mate Darryl Fitton 3-0 in the first round, losing just one leg along the way. Bookmakers slashed his odds of winning the championship from 16/1 to 9/2 after this performance, but he was unable to produce the same standard against Jan Dekker in the second round and lost 4-1. During this tournament commentators and pundits began affectionately referring to Kellett as the 'cocky craftsman' (in a nod to Eric Bristow), due to his confidence on-stage in comparison to his otherwise humble nature off it.

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Wikipedia