The pair turned 29 on Friday (12Jun15) and marked the occasion a day later by hosting a bash dubbed the 'Olsen Olympics' at a house in New York's The Hamptons.

Guests were divided into two teams and wore T-shirts emblazoned with the slogans "Team Mary-Kate" and "Team Ashley" to compete in a number of outdoor games, including an obstacle course and dunk tank.

In the end, Team Ashley was crowned victorious. The day was documented in a series of pictures posted on