Lucas (루카스) is a Chinese-Thai singer under SM Entertainment. He is a member of the Korean pop boy group NCT and its sub-units NCT U and WayV. He was formerly a member of the pre-debut team SM Rookies.
- Stage Name: Lucas (루카스)
- Real Name: Wong Yuk Hei (Cantonese), Huang Xu Xi (Mandarin) (黃旭熙)
- Birthdate: January 25, 1999
- Birthplace: Hong Kong, China
- Blood Type: O
- Height: 184cm
- Weight: 64kg
- Education: T.W.G.Hs. Yow Kam Yuen College
- Specialties: English, Korean
-  Ten - Dream In A Dream
- He is half-Thai (Mother) and half Chinese (Father).