The Oasis rocker was enjoying a drinking session with friends at The Old White Bear pub in Hampstead, north west London, but the evening took a bizarre turn when the inebriated singer tried to mount a frightened pup and left a waitress in tears after leaving the bar without paying his £300 tab.
Fellow drinker Emma Ainsworth told The Sun newspaper: "He was absolutely hammered. He tried to get on the dog's back and they were just taking little steps -- but it just didn't work. It was really funny."
The 40-year-old star is said to have enjoyed numerous Jack Daniel's and Coke with seven friends, as well as expensive bottles of Billecart-Salmon champagne, which cost £47 each, at the trendy gastro pub - but when it came time to settle his bar tab, Liam was nowhere to be found.
An onlooker said: "The poor waitress serving them was crying when she thought she'd lost all the money, but the pub manager ran after him."
It seems the matter was quickly settled, however, as the bar manager added: "After £300 of drink you forget things. He was happy to pay straight away when I caught up with him."