Kettings has spent spells on loan at Birmingham City, Morecambe and York City, and is now looking forward to developing his game at Selhurst Park, having penned a two-year contract with the Eagles.
He told reporters: "I'm delighted because this is a massive club. Everyone who I've spoken to about Crystal Palace has only had good things to say so I think it's a massive opportunity for myself and a good club to come to.
"I'm really looking forward to working with both Julian Speroni and Wayne Hennessey as they'll both be able to teach me things and give me new perspectives so it'll be good for me to work with them.
"I had a really good relationship working with George Wood when he was at Blackpool as he was inspirational and helped me progress when I was 18 years old. I developed a lot under him and hopefully I can develop even more here."
Kettings signed professional terms at Blackpool in 2011, but never made a senior appearance for the Tangerines.