The D Line Subway Extension Project, formerly known as the Westside Subway Extension, the Subway to the Sea, and the Purple Line Extension, is a construction project in Los Angeles County, California, extending the rapid transit D Line of the Los Angeles Metro Rail system from its current terminus at Wilshire/Western in Koreatown, Los Angeles, to the Westside region. The project is being supervised by the Los Angeles County Metropolitan Transportation Authority (Metro). The subway has been given high priority by Metro in its long-range plans, and funding for the project was included in two county sales tax measures, Measure R and Measure M.

Wilshire/La Cienega station is an under construction, underground rapid transit station on the D Line of the Los Angeles Metro Rail system in Beverly Hills, California, at the intersection of Wilshire Boulevard and La Cienega Boulevard. It is in the design/construction phase of the D Line Extension project. The tunneling work from the east was completed in May 2021 and the tunneling work from the west (Wilshire/Rodeo) was completed in January 2023. Originally the project was slated for completion in 2023. The station's opening is now scheduled for 2025.