Dear X

Director

• 
  Lee Eung Bok
• 
  Park So Hyun

Original Creator

• 
  Vanziun

Screenwriter

• 
  Choi Ja Won

Main Role

• 
  Kim You Jung

  Baek A Jin

  Main Role
• 
  Kim Young Dae

  Yun Jun Seo

  Main Role
• 
  Kim Do Hoon

  Kim Jae O

  Main Role
• 
  Lee Yul Eum

  Im Re Na

  Main Role

Support Role

• 
  Kim Yi Kyeong

  Sim Seung Hui [A Jin’s rival]

  Support Role
• 
  Kim Yoo Mi

  Hwang Ji Seon [Jun Seo's mother]

  Support Role
• 
  Bae Soo Bin

  Baek Seon Gyu [A Jin's father]

  Support Role
• 
  Kim Ji Young

  Seo Mi Ri [Longstar Entertainment CEO]

  Support Role
• 
  Hyun Seo Ha

  Seok Hyang I [A Jin's manager]

  Support Role
• 
  Hong Bi Ra

  Moon Do Hui [Mi Ri's right-hand man]

  Support Role
• 
  Shin Moon Sung

  Park Dae Ho [Detective on Nojeong-dong case]

  Support Role

Guest Role

• 
  Park Seung Tae

  Hong Gyeong Suk [In Gang's grandmother] (Ep. 6)

  Guest Role
• 
  Kim Seong Kyeong

  Yi Ye Na [A Jin's classmate] (Ep. 1)

  Guest Role
• 
  Bae Jin Ah

  Mrs. Kwak [Homeroom teacher] (Ep. 1)

  Guest Role
• 
  Jung Jong Hoon

  [Principal] (Ep. 1)

  Guest Role
• 
  Ma Jung Pil

  [Seong Hui's father] (Ep. 1)

  Guest Role
• 
  Hyun Jin

  [Seung Hui's mother] (Ep. 1)

  Guest Role
• 
  Yoon Joo

  [Class 2-4 teacher] (Ep. 1)

  Guest Role
• 
  Gi So Yoo

  Baek A Jin [Child] (Ep. 1-2)

  Guest Role
• 
  Lee Seo An

  Im Sun Ye [A Jin's mother] (Ep. 1-2)

  Guest Role
• 
  Kang Ian

  [Art teacher] (Ep. 1-2)

  Guest Role
• 
  Park Hoo

  Yun Jun Seo [Child] (Ep. 2)

  Guest Role
• 
  Choi Jae Yoon

  Kim Jae Ung [Jae O's brother] (Ep. 2)

  Guest Role
• 
  Gu Bon Jin

  [Jae O's father] (Ep. 2)

  Guest Role
• 
  Jung Eun Ran

  [Housekeeper] (Ep. 2)

  Guest Role
• 
  Im Yu Ran

  [Convenience store owner] (Ep. 2)

  Guest Role
• 
  Kim Ji Hoon

  Choi Jeong Ho [Xanadu Coffee owner] (Ep. 2-4, 7-8)

  Guest Role
• 
  Kim Il Woo

  Hong Su Hyeok [Grandpa Yun's secretary] (Ep. 2-3, 5, 9-10)

  Guest Role
• 
  Jeon Gook Hwan

  [Jun Seo’s grandfather] (Ep. 2-3, 5)

  Guest Role
• 
  Son Kang Gook

  An Do Gang [Jae O's boss] (Ep. 2, 6, 9-10, 12)

  Guest Role
• 
  Kim Sang Il

  Im Seung Yong [PB Agency CEO] (Ep. 3)

  Guest Role
• 
  Lee Seung Jin

  [Detective] (Ep. 3)

  Guest Role
• 
  Baek Sun Ho

  [Xanadu Coffee customer] (Ep. 3)

  Guest Role
• 
  Hong Min Gi

  [Xanadu Coffee customer] (Ep. 3)

  Guest Role
• 
  Cha U Yeong

  Ham Yeong Su [Police] (Ep. 4)

  Guest Role
• 
  Kim Se Yun

  [Detective] (Ep. 4)

  Guest Role
• 
  Kim Jae Il

  [Internal affairs officer] (Ep. 4)

  Guest Role
• 
  Choi Sol Hui

  [Jae O's aunt] (Ep. 5)

  Guest Role
• 
  Seo Hye Jin

  [Publisher company staff] (Ep. 5)

  Guest Role
• 
  Hwang In Youp

  Heo In Gang [Idol-turned-actor] (Ep. 5-8)

  Guest Role
• 
  Ryu Kyung Hwan

  Im Hui Guk [Re Na's reporter cousin] (Ep. 6-8)

  Guest Role
• 
  Yoon Hyun Soo

  Ryu Ji Hyeok [In Gang's former bandmate] (Ep. 6)

  Guest Role
• 
  Lee Ung Jae

  Heo In Mo [In Gang's younger brother] (Ep. 7-8)

  Guest Role
• 
  Jung Woo

  Director Seol (Ep. 8)

  Guest Role
• 
  Park Seong Kyun

  [News editor] (Ep. 8)

  Guest Role
• 
  Kim Min Song

  [Man with X tattoo] (Ep. 8)

  Guest Role
• 
  Jang Eun Seo

  [Gyeong Suk's neighbor] (Ep. 8)

  Guest Role
• 
  Kim Min Che

  [Gyeong Suk's neighbor] (Ep. 8)

  Guest Role
• 
  Hong Jong Hyun

  Moon Do Hyeok [A Jin’s fiancé] (Ep. 8-12)

  Guest Role
• 
  Lim Seung Beom

  Secretary Kim [Do Hyeok's right-hand man] (Ep. 8-12)

  Guest Role
• 
  Kim Gyu Do

  [Do Hyeok's agency CEO] (Ep. 9)

  Guest Role
• 
  Choi Ji Yeon

  [Reporter] (Ep. 9)

  Guest Role
• 
  Oh Jae Se

  [Detective in Longstar office] (Ep. 9)

  Guest Role
• 
  Go Seo Hee

  Maid Kong [Do Hyeok's servant] (Ep. 10)

  Guest Role
• 
  Park Boo Gun

  Director Park (Ep. 10-11)

  Guest Role
• 
  Park In Chun

  [Landlord actress] (Ep. 11)

  Guest Role
• 
  Park Sang Hwi

  Han Ji Gyu [PD] (Ep. 11)

  Guest Role
• 
  Han Hae Sol

  [Department store employee] (Ep. 11)

  Guest Role
• 
  Kang Min Ji

  [Do Hyeok's ex-wife] (Ep. 11)

  Guest Role
• 
  Kim Nam Hee

  Han Ji Gyu [Documentary producer/host] (Ep. 11-12)

  Guest Role
• 
  Park Jun Seo

  [Red carpet man]

  Guest Role
• 
  Kim Jung Hwan

  [Broadcasting station director] (Ep. 12)

  Guest Role

Cameo

• 
  Cho Mi Yeon

  [Host] (Ep. 6)

  Cameo