The 29-year-old actress and her boyfriend Ashton Kutcher were joined by the 24-year-old royal and her partner Dave Clark, 30, for dinner on Saturday (11.05.13) before embarking on a pub crawl to several upmarket cocktail bars in London.
The quartet first enjoyed dinner at the Duck & Waffle restaurant on the 40th floor of Heron Tower, before moving on to enjoy tequila cocktails at the nearby Callooh Callay bar.
From there, they finished evening at the John Salt bar in Islington, where they had more drinks and some snacks.
John Salt boss Leigh Gillson told The Sun newspaper: ''They asked for our best speciality dish. We gave them deep fried banana in caramel.''
A source added: ''It wasn't a boozy bender, more an upmarket crawl.''
Mila and Ashton, 35, are currently living in Hampstead, north west London, while she shoots new movie 'Jupiter Ascending', but it was recently revealed they are planning a break out of the city on a riverboat on the Norfolk Broads, East England.
A source said recently: ''Ashton thinks it will be a great experience. They've got no qualms about staying on a boat. They won't exactly be roughing it.''