After enduring a heartbreaking loss soon after giving birth, Momo the brave mother cat captured many hearts in this viral video.

On TikTok and Instagram, Leo Ching Ling documents her life with Momo, who recently gave birth.

Ling told Newsweek the pregnancy came as a shock: "It came as a surprise; we thought she would be due end of the week, but she suddenly found a random box and gave birth."

Although she and her boyfriend had already prepared a cozy nest for Momo, the kitty chose her own place to give birth in a cardboard box.

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"It seems like her first three kittens were a smooth and quick labor, around three hours, and all of them are out and drinking milk already," Leo explained.

"We thought her labor was over by around 10 p.m., since she was feeding her three kittens and even ate dinner herself. We watched her till around 12 and went to sleep."

But tragically, the joy was soon followed by sorrow. The next morning, Leo discovered the lifeless body of the fourth kitten.

"We thought [Momo] didn't feel much about it as she moved out of the box after losing the kitten, but later on, after settling the other kittens down, she actually came over and sat by the empty box for a while several times, just looking into space," the pet owner said.

"We don't know how she feels or whether she knows, but she was definitely mourning for a while."

The three surviving babies were weak at first, but they are now doing much better. According to Leo, there's even a waitlist of people who want to adopt them once they're old enough!