Jeremy McWilliams signed his contract with Kenny Roberts on Monday to ride a Proton KR3 in next year's world GP championship.
" I am really happy to have a rider like Jeremy on board, " said Roberts.
" He has a lot of experience on a lot of different bikes which will help him contribute a great deal to our programme.
" You know with Jeremy he will always give 100 per cent. He has experience and he has speed, " Roberts added.
The Ulsterman, who last season became the first Briton to win a GP in 15 years with his 250 success at Assen, signed a deal to race the lightweight three-cylinder 500 two-stroke alongside Japan's Nobuatsu Aoki.
The 37-year-old was on the market after a deal with his works Aprilia 250 squad collapsed at the final GP in Brazil back in November but his future was resolved when he signed a one-year deal with Banbury-based Team Roberts.
McWilliams, who last raced in the premier class back in 2000 when he partnered Tetsuya Harada on the works Aprilia V-twin 500, said: " At first it seemed that the new four-strokes would be so powerful they would run away, but at tests new 500 rider Daijiro Katoh was faster on a two-stroke. It also seems there's a question of tyre endurance.
"That has given me a lot of hope for the 500 two-stroke, and the feeling that four-strokes may not be the way forward just yet. The KR3 proved last season it is capable of qualifying well. My aim is to achieve the same lap times and results in the race."
McWilliams is expected to test the bike for the first time next month and he added: "Already they are making changes to the machine that I will be testing in January. I've had discussions with the engineers and we're thinking along the same lines. The primary goal is to make this machine achieve its full competitive potential."