Degrees of irreducible representations over a splitting field cannot all be distinct

Statement
 Suppose $$G$$ is a finite group and $$K$$ is a splitting field for $$G$$ (in particular, the characteristic of $$K$$ does not divide the order of $$G$$). Then, the degrees of irreducible representations of $$G$$ over $$K$$ cannot all be distinct. In other words, there exist two irreducible linear representations $$\varphi_1,\varphi_2$$ of $$G$$ over $$K$$ that are not equivalent as linear representations but have the same degree.