The 33-year-old joined the likes of Gary Anderson, James Wade and Ian White on Team Unicorn on Monday. Klaasen, the youngest man ever to win a darts World Championship, is the current world number 17. The Cobra struggled for form in 2017 due to a wrist injury, but is hoping for better this year.
"I couldn’t practice for a long time because of the injury. There are no shortcuts for a good and permanent recovery but I’m nearly there," he said.
The Dutchman spoke of his delight at joining one of the world's most prominent darts manufacturers.
He said: “It is an honour for me to join Team Unicorn and it is a huge boost for me at this stage of my career.
“There is no doubt in my mind that Unicorn will help me to take my game to a higher level and make everything I need to be a better player. I have some ideas and I can’t wait to get started with developing new darts.”
Returning to the world's top 16 is a priority for the Cobra.
“I know I can win tournaments and TV tournaments as well. My A game is good enough and I am working very hard on becoming more consistent. Unicorn will come up with the perfect darts, then it is up to me," he said.
Join the Fantasy Premier League Darts! Create 1 team for 5 euro for the full Premier League season. The prize pool starts at 568 euro and we have a 1st prize of at least 100 euro! https://twitter.com/UnicornDarts/status/957998403664924672