Dean Campbell has joined up with former Dons manager, Derek McInnes at Rugby Park.
Dean goes on loan to Kilmarnock until the end of the season.
The 20-year-old has made 75 appearances for the first team since making his debut in 2017 against Celtic aged 16, in doing so becoming the youngest ever Don. The Youth Academy graduate won the AFC Young Player of the Year award in 2019–20.
Capped by Scotland at U19, U18 and U17 age groups, Dean signed a three-and-a-half-year extension to his contract in December 2019.
Speaking to the club website, Stephen Glass said: “Dean is at an important stage of his career and for the benefit of Dean, and for Aberdeen next season, he is heading out on loan to play competitive football at a good level.
“Despite his young age, Dean has been in and around the first team for quite a number of years now but this will be his first loan spell. It is a great opportunity for him to go and show the quality that he has.”
Dean added: “This loan spell will give me the chance to challenge myself, playing regular football, in a tough league. I want to go and make a real contribution to the team as they still have much to play for this season.
“My goal is to return to Pittodrie to continue my development and be ready to make an impact next season.”