Becky Pritchett is previously mentioned in Season 8; Episode 11: Sarge and Pea (2017). Jay said "30 years ago, I didn't do your Aunt Becky's closets for free. The whole family got together and decided I was cheap called me "High Pockets." to explain his expensive gift.
Becky Pritchett is mentioned in Season 2; Episode 2 The Kiss (2010). Jay says that his father only kissed him once and it was on the back of the head when he said "Goodnight, Becky", thinking Jay was his sister.