Sekai de Ichiban Shiawase!

The series follows ex-shut-in Koutarou Sano, who, thanks to his favorite minor idol, is able to enter society. Through a chance encounter, Koutarou runs into his favorite idol at a beef bowl restaurant. Kei is retired from the entertainment business now, but that doesn't stop him from making an unbelievable request.

(Source: Anime News Network)