Zach Galifianakis is looking trim and happy after making changes to his lifestyle.

The 47-year-old Hangover star has shed an estimated 23 kg after quitting drinking in 2014.

He also revealed he lost weight by going for long walks.

'I stopped drinking and I just kind of put the weight off,' he joked with Conan O'Brien in 2014. 

'I was having a lot of vodka with sausage. Delicious but bad for you.'