Robert De Niro's partner, Tiffany Chen, reveals she had Bell's palsy after giving birth to their baby. Here's what the condition is and how it's treated.

• Robert De Niro's partner said she experienced Bell's palsy after giving birth to their daughter.
• Tiffany Chen told CBS Mornings that she experienced symptoms when she got home from the hospital.

Tiffany Chen, Robert De Niro's partner, told "CBS Mornings" in a segment set to air Friday that she was diagnosed with Bell's palsy after giving birth to their daughter, Gia Virginia Chen De Niro, in April.

Speaking to host Gayle King, Chen revealed that when she went home from the hospital, her "tongue felt strange," and she was experiencing tingling and some numbness.

"My face just felt weird," Chen told King. "I didn't know what the feeling was that I was having."

When Chen got home, she said she looked at herself in the mirror and her face looked like "everything was just starting to fall down on itself."

"My face was melting on itself," Chen told King.

Bell's palsy is a condition that causes numbness or weakness on one or both sides of the face, according to the Mayo Clinic. In Chen's case, she said she experienced the condition on both sides of her face.

As well as facial paralysis, symptoms can include drooling, headaches, hypersensitivity to sound, and loss of the sense of taste in the front two-thirds of the tongue.

Symptoms suddenly appear over a 48 to 72-hour period and generally start to improve with or without treatment after a few weeks. Bell's Palsy does not usually cause any long-term health issues, and it can be treated with a number of different medications, including steroids to reduce swelling, and antivirals.

According to the National Institute of Health, the condition is estimated to affect about 40,000 people in the US every year. While it can affect anyone of any gender or age, most people who experience Bell's palsy are between 15 and 45 years old. Pregnancy is a known risk factor for the condition.

What causes Bell's Palsy is unknown, but it is thought to be a result of inflammation directed by the body's immune system against the nerve that controls movement in the face, according to John Hopkins Medicine.

Chen told King that it "all hit" when she was a week postpartum. She said she called her doctor after trying to eat when a mouthful of food fell out of her mouth. Then, she said, she was "starting to slur."

Her doctor told her to go to the hospital, where she was immediately admitted, she told King.

"I lost all facial function the minute I got into the hospital," Chen said.