They accompanied their grandchildren to classes Wednesday, confabed with Headmaster Drew Casertano and had lunch in the private, prep school’s new dining hall.
They then took to the athletic fields to support the school's teams.
School officials said the Mustangs earned multiple victories, including a varsity field hockey win against a team from the Hotchkiss School in a pre-season scrimmage.
Hotchkiss is a private boarding and day school in Lakeville.
The boys' varsity soccer team also defeated their foes from the Forman School, a private boarding and day school in Litchfield, Conn.
According to a post on the its website, the school said Grandparents Day is an “opportunity for students to become tour guides for their loved ones, sharing a glimpse into their daily life, and into what makes Millbrook, Millbrook.”
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