Brilliant

You gain proficiency with one skill, one tool or one language, and you gain expertise with one skill. (This is The Prodigy Feat)

Choose one skill in which you have proficiency. You gain expertise with that skill, which means your proficiency bonus is doubled for any ability check you make with it. The skill you choose must be one that isn't already benefiting from a feature, such as Expertise, that doubles your proficiency bonus