Steve McCormack has resigned as Widnes coach to become Justin Morgan's new assistant at Hull KR.
McCormack took the Vikings to within 80 minutes of a return to Super League in each of his two seasons but felt he had taken the club as far as he could.
"I have a burning desire to succeed at the highest level and I'm grateful for this chance," said the 34-year-old.
He has signed a two-year deal with Rovers and will replace Andrew Webster, who has failed to obtain a work permit.
Morgan added: "Steve is a welcome addition and he's a coach with vast amounts of experience that will benefit the club. I'm looking forward to Steve joining the team and working with him next year."
Widnes are looking for new owners after going into administration and have witnessed the break-up of the side that lost to Castleford in the promotion-deciding National League Grand Final earlier this month.
"It has been a challenging and enjoyable two years at Widnes and I am sad to leave," said McCormack.
"It will be a great challenge for me coaching at a Super League club again, and one I'm excited to be part of, I'm looking forward to working with Justin and the players."
McCormack is the youngest man to coach in Super League - he was just 28 when he was appointed at Salford in 2001 but was sacked as the Reds faced the prospect of relegation.