The 35-year-old actor, who was in the city with his girlfriend Mila Kunis, was spotted buying stock of tea, reported Daily Star.
"No-one could believe their eyes when they saw Ashton in a supermarket. We were more surprised when he bought around 12 boxes of Yorkshire tea bags," said a source.
Kutcher began dating his former 'That 70s Show' co-star Kunis in 2012.