Red Velvet's Wendy will lend her voice for a new OST of JTBC drama 'D-Day'.

The song is titled 'Let You Know' and was first played during episode 7 on October 9th, attracted much attention from the viewers.

This will be the third time Wendy will be participating in a drama OST, following 'Because I Love You' in mini drama 'Mimi' and 'Return' from 'Who Are You: School 2015'.

'Let You Know' will be released through various online music sites on October 16 at noon.