A Big Brother housemate just served up the sourest move yet — and trust us, you wouldn’t risk her anywhere near your welcome mat after seeing this!

Catch this clip that was caught on the live feed from “Big Brother” S27 — housemate Mickey cracks open a fresh bottle of lemonade, chugs straight from the rim … then pops it right back in the communal fridge like nothing happened.

Total nightmare — the communal fridge, everyone’s drinks, and not a soul around to catch her in the act … meaning the house had no clue Mickey’s germs were already swimming in their lemonade!

Unclear if production swooped in to yank the polluted juice to save the housemates — but either way, the moment had X fans gagging online, branding it flat-out gross.

Some BB fans have defended Mickey in the comments, saying it was her own personal lemonade that she got when she was the Head of Household and now just keeps it in the communal fridge.

Clearly, she’s squeezing the life out of the house!