Kenny Shiels has become the assistant manager to Mixu Paatelainen at Kilmarnock.
The former Coleraine, Ballymena United, Larne and Carrick Rangers boss quit his job as Tranmere Rovers' head of youth development to take on the new challenge.
Shiels spent three years with the League One club but he has now agreed to lend a helping hand to Paatelainen.
Experienced coach Shiels, who guided the Northern Ireland Under-17 side to the European finals, said: “I'm sad to be leaving Tranmere, but this is a really exciting opportunity for me.
“It was a hard decision to leave Tranmere as it's a club you fall in love with.
“I like to think I've made a positive impact on the future of the club through my work with the centre of excellence and hopefully the results will be seen over the next few years in the first team.
“There are some very dedicated, hard working people here who work for each other and it was a pleasure being a part of that. Tranmere will always hold a place in my heart as they gave me the opportunity to progress in my coaching career.”
Kilmarnock's website stated: “Kenny is a Uefa Pro Licence holder and will bring an array of knowledge to the club.”
Tranmere boss Les Parry said: “I'm really sorry to see Kenny leave the club, but this is too good an opportunity for him to turn down.”
Chief executive Mick Horton said that Tranmere “cannot stand in the way of this move” and thanked Shiels for his service to the club.
Shiels will aim to keep Kilmarnock in Scotland's top flight despite tight budget cuts.