The role of rare-earth atomic 'collapse' in the formation and thermodynamics of aluminium-rich metallic glasses is studied, using the example of the Al90La10 metallic glass. Monte Carlo simulations are carried out for structural models containing 500 atoms in a cubic cell with periodic boundary conditions. The change of the pair interaction due to the atomic collapse is taken into account. An equivalent Ising Hamiltonian, accounting for the collapse transitions, is introduced. The Ising Hamiltonian is used to calculate the temperature dependence of the specific heat, which exhibits two temperature humps associated with the decollapse of the La atoms. The corresponding temperature is close to the experimentally measured temperature at which crystallization of the glass begins.