"How I Met Your Mother" star Cristin Milioti had to keep the Mother of All Secrets. Tonight, finally, the secret is on display.

When the "Once" star found out she was cast as the Mother in "How I Met Your Mother," she told her furniture-making boyfriend, whom she shares a flat with in Brooklyn, and her own mother, swearing them both to keep her confidence. "My job and financial future literally depended on it," the 28-year-old New Jersey native told them.

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