It's the end of an era: the "Got Milk?" ad campaigns, which made the "milk mustache" cool again, is finally being retired after a 20-year run that featured a cadre of celebrities ranging from supermodels (Naomi Campbell) to game show hosts (Alex Trebek) to boy bands (The Backstreet Boys).

So, as the new campaign -- "Milk Life" -- is launched today, let's take a look back at five of the most notable "Got Milk?" campaigns that have been launched over the past 20 years.

Beyonce AND her mother, Tina Knowles: before she was Mrs. Jay-Z, Beyonce and her mother, Tina Knowles, teamed up for this ad campaign that was meant to promote their House of Dereon fashion line. (Cute little jab at her father, Matthew Knowles, as well...)

Steven Tyler: Aerosmith's front man opened up wide and said "AHHHH!!" for his milk ad.

Lindsay Lohan: A fresh-faced rising star named Lindsay Lohan showed all the hope in the world during her Got Milk? campaign. Those were the days...

Billy Ray Cyrus: Before he was known as "Miley's dad," the one-hit wonder country star posed for this absolutely HILARIOUS "Got Milk?" ad that, I'm sure, someone told him looked "sexy."

Britney Spears: This ad gave you Double the Britney. At the height of her popularity, the former Mousketeer posed in a milk mustache alongside her childhood self.

So, which was your favorite Got Milk? ad from the past 20 years?