Coffee Prince(2012)

Original title: คอฟฟี่ปรินซ์ วุ่นรักเจ้าชายกาแฟ ไทย

Win is a middle-aged guy from a rich family who has never had to work until his grandmother forces him to run a coffee shop. Nat is a hardworking and tomboyish girl who is often mistaken for a guy. She pretends to be male to get a job at the coffee shop but she and Win gradually begin to develop feelings for each other.