Hybridization has been documented to the extent where its importance for generating evolutionary novelty can no longer be questioned. In spite of this, we lack an understanding of the evolution of regulation of gene expression in hybrids, and its role in hybridization derived novelty. Gene expression evolves in a stabilizing manner where cis(local)- and trans(distal) regulatory elements co-evolve. As hybridization breaks up co-inheritance of regulatory elements transgressive hybrid expression patterns, transcending the ranges of both parent species, may arise in spite of intermediate genome composition. I propose to leverage my finding of transgressive gene expression in a wild hybrid species and address how hybridization produces transgressive gene expression. This research will give insights into how hybridization can contribute to the arrival of the fittest, by producing novel variation that selection can act on. This is an ERC COG funded project leveraging the hybrid Italian sparrow as a study system.