In a statement issued to PRWeek, Villalon said she was leaving to 'pursue new career experiences'.
Cubitt co-founder and managing partner Simon Brocklebank-Fowler said Villalon's position would be merged with that of co-head of IR Bernard Compagnon, who joined the firm from Taylor Rafferty at the end of last year.
Brocklebank-Fowler said he was stepping back from the day-to-day running of Cubitt in favour of former JP Morgan Funds Hub sales and marketing director Gareth Thompson, who joined the firm in January and has taken on the new role of chief operating officer.
Although Brocklebank-Fowler keeps the title of managing partner he now focuses on client work and business development strategy.
Villalon's exit follows that of partner Fergus Wylie (PRWeek, 22 October 2004) and leaves Brocklebank-Fowler the last remaining of the four who founded Cubitt with Nabarro Wells chairman Nigel Atkinson in 1998.
Wylie subsequently became deputy chief executive of Gavin Anderson London and his equity was sold back and divided between Cubitt's ten partners.