We performed a theoretical study of the main effects of a planet ingestion on the structure/chemical composition/evolution of a pre-MS star. We applied our analysis to the Gamma Velorum cluster member 2MASS J08095427-4721419, which shows a peculiar over-abundance of metals. We analised the effects on the star of changing the characteristics of the accretion episode, in particular the age at which the planet ingestion occurs, the planet mass and its chemical composition.