Takeuchi is among a series of Japanese celebrities who have taken their own lives this year. She was reportedly found unresponsive by her husband, actor Nakabayashi Taiki, at their home in Tokyo around 2 AM on Sunday. She was later pronounced dead in hospital and Tokyo police say they suspect she took her own life.
Takeuchi gave birth to a baby son in January. Her husband reportedly said there was nothing unusual about her on the day she died.
Takeuchi's acting career spans more than two decades. Her many prizes including outstanding actress in a leading role at the Japan Academy Awards. She is known worldwide for her role in "Miss Sherlock", co-produced by HBO and Hulu.
Takeuchi's agency Stardust Promotion issued a statement saying it was stunned and saddened by her death, a feeling that resonated across Japan.
Tributes have been pouring in from across the world with many people posting on Takeuchi's Instagram page. Among her fans is Hong Kong pro-democracy activist Agnes Chow, who wrote in Japanese, "Too many sad things happened this year. I try to take it in, but haven't been able to do so. I pray for her soul."
Japan has seen a string of high-profile suicides in recent months including 30-year-old actor Miura Haruma, actress Ashina Sei, 36, and reality star Hana Kimura, 22.
A group that represents entertainers says the stay-at-home culture has caused stress and could have led some to spend more time worrying about their future. The group is calling on the industry to put in place a system to better detect and manage cases of anxiety.
The Japanese government's chief spokesperson, Kato Katsunobu, expressed concern about possible repercussions.
"Celebrity suicides and their coverage by the media can have an enormous impact," said the chief cabinet secretary. "In some cases, they could cause or lead to other people ending their lives."
Shimizu Yasuyuki from the Japan Suicide Countermeasures Promotion Center said the coronavirus pandemic has caused emotional distress for many.
"The pandemic has led people to be physically separated from each other," he said. "It's now become more important than ever to keep in touch and to share our feelings with friends and family."
Japan's health and welfare ministry is advising people with mental health problems to visit the website: