Kammala wannan jumla: A watan Afrilu 2003, babban kocin kungiyar kwallon kafa ta kasar Morten Olsen ya kira Kahlenberg zuwa tawagar a karon farko. Ya fara bugawa tawagar kasa wasa, ya shigo a matsayin mai maye gurbin minti na 76, a wasan sada zumunta da Ukraine a ranar 30 ga Afrilu 2003. A watan Maris na shekara ta 2004, an kira Kahlenberg zuwa manyan 'yan wasa sau ɗaya kuma ya yi wasan na biyu don Denmark, yana zuwa a matsayin mai maye gurbin minti na 78, a cikin asarar 2-0 da Spain a ranar 31 ga Maris, 2004. A watan Mayun 2004, an zaba shi a matsayin dan wasan Danish mafi ƙanƙanta don
Gasar Zakarun Turai ta 2004. Koyaya, Kahlenberg bai buga wasa ba a gasar, saboda an sanya shi a benci mai maye gurbin.