One of Heroes' most fashionable stars is gonna have an all-new reason to go dress shopping. Ali Larter is engaged her longtime boyfriend, actor Hayes MacArthur. The proposal took place this weekend, according to People. And it wasn't a moment too soon. "I told my boyfriend after three weeks that I wanted to marry him and that we could do it tomorrow," said Larter in the October issue of Cosmopolitan. Congrats, you two!