The `Home Alone` star and the `Black Swan` actress called time on their eight-year relationship but have pledged to remain friends.
A spokesperson for the couple said: "The split was amicable, and they remain close friends."
Though news of the separation has only just been made public, it has been claimed that the couple split months ago but decided to keep the news private while Mila promoted her new movie `Black Swan`.
Despite being with Macaulay, 30, for eight years, 27-year-old Mila had previously revealed so had no intention to marry the former child star.
She previously said: "Not to say that I don`t believe in it, but it`s just not something that`s important to me. But I will have children. I`m too selfish to have them now, but when I do, I don`t feel like I need to be married."
Macaulay - who shot to fame in 1990 playing Kevin McCallister in `Home Alone` - was previously married to actress Rachel Miner, who he wed when he was just 18 in 1998 before splitting up two years later.