Golden Goose PR will promote the title's first celebrity guest editors and its second anniversary.
The agency won the brief after a competitive pitch and will target 25 to 45-year-old ‘AB' women.
Scarlet launched in 2004 and made headlines last year when big-name retailers refused to stock the title, which features explicit copy and erotic fiction. The title is now widely available.
The magazine sells around 35,000 copies a month.