[4] The circle line will be numbered 13 and coloured blue violet on official transit maps.

[5] Before 4 July 2024, the circle line was coloured grey on its official alignment map.

Interest in building the line resurfaced in early 2015;[7] the project was shelved by former Prime Minister Mahathir Mohamad in May 2018[8][9] but was later on revived in November 2020.

The circle line is expected to stretch while forming a loop from Bukit Kiara to PPUM and it will include densely populated areas such as Mont Kiara, Segambut, KL Metropolis, Titiwangsa, Setapak, Setiawangsa, Ampang, Salak South, Pandan Indah, Pantai Dalam, Cheras and Universiti Malaya.

Connected to KL Gateway Mall and will serve the Bangsar South district.