Understanding triggers and evolution of post-depositional sediment intrusion is of major importance to decrease the risk associated with hazards to infrastructure and environment from events such as submarine landslides and fluid escape. Whereas deep-sourced intrusions (>1 km) are widely documented, early burial examples are poorly recognized and have been described only in large deltas. Their formation had not yet been documented in deformed foredeep. Here, we show an exceptionally well-exposed, early burial mud diapir in the Northern Apennines fold and thrust belt. Disequilibrium compaction and tectonic basin tilt led to lateral pressure migration within shallow (<200 m) sediments. As a result, near-lithostatic overpressure developed at the basin margin causing sediment intrusion and destabilization of the slope. This work shows that early burial mud diapirs can develop in deformed foredeep with similar characteristics to their deep-rooted counterparts, with important implications for hazard assessment in areas non-traditionally prone to shallow overpressure buildup.