Ashley Olsen Prepares Birthday Bash

Ashley Olsen steps out of her $22,000-a-month party house in Malibu to get her java fix at a Starbucks on Sunday.

America’s most famous set of twins plan on celebrating her 21st birthday on June 13 - when they hit the legal drinking age — at their two-bedroom, two-bathroom bungalow.

Says In Touch Weekly’s source, “Ashley and MK [her twin sister Mary-Kate] plan to spend much of the summer in Malibu.”

Party on, pint-sized moguls!