The woman who is known as Lim Ji-hyun, fled to South Korea in 2014, where she became a popular TV celebrity.
However, a woman resembling her appeared in a propaganda video in the North's capital on Sunday - prompting speculation she may have been kidnapped.
In the video, she says she was lured away and forced to defame the North.
She says that she voluntarily came back across the border.
Ms Lim had been a popular face on South Korean television, appearing on both talk shows and reality TV programmes.
The authorities have not yet made sure if the woman in the propaganda video is Ms Lim. However, they believe Ms Lim is back in North Korea.
The propaganda video has been released on Youtube by the North Korean Uriminzokkiri website on Sunday.
In the video uploaded, the woman introduces herself by another name, Jeon Hye-Sung
Source: BBC