*

Two-dimensional transition metal dichalcogenides exhibit highly unusual and layer-dependent electronic structure, caused by quantum confinement effects. The results of these changes have been widely documented in their valley-dependent optical properties. The impact of electron-electron interactions on the carrier dynamics is however at present less clear. Here we report on the attosecond dynamics in MoS₂ as a function of carrier density in the conduction band. We show that increased electron density in the conduction band leads to orbital rehybridization, which is the source of the observed layer decoupling. These effects are also clearly observed in the electronic structure in the conduction band region. Our results uncover the many-body effects that govern the electronic properties of MoS₂ and likely other 2D materials.