A widely-available brand of lager. Although the version brewed under licence and marketed in the UK is touted as a premium brand with the slogan "refreshingly expensive", in its native Belgium it is just your ordinary, bog-standard pilsner of the sort you get when you order "un pression" or "een pintje". Note that in Belgium such beers are not really considered as alcoholic drinks and are available from Coke machines and to be found under "eaux" on menus. An Interbrew product, of course.
The Belgian marketing campaigns are mainly based on the proposition that "Thuis is waar m'n Stella ligt" - roughly "wherever I lay my Stella is my home".