Liam is seen looking very 80s as he poses in the short wig with a pink headband, while wearing a white polo shirt, grey sweater and baggy jeans.
This is now the second teaser to be unveiled to fans, after bandmate Niall Horan's character was revealed on Tuesday (16 July).
An additional trailer, which features 21 seconds of their song, showed Niall in a suit with plenty of facial hair, playing a middle-aged studio executive named Harvey.
Remaining bandmates Harry Styles, Louis Tomlinson and Zayn Malik are yet to be unveiled, but the official One Direction Twitter account will post each band's makeover every day in the build up to the music video premiere on 23 July.
'Best Song Ever' will be the first single lifted from One Direction's third studio album. The single also features in the boys' upcoming 3D movie This Is Us, which will hit UK cinemas on 29 August.
Listen to a preview of One Direction's new single 'Best Song Ever' in the trailer below: