Episode 15 of MBC's 'Triangle,' which aired on June 23, had a pleasant surprise for fans as T-ARA'S JIYEON made an appearance as a potential partner for the chaebol son, played by ZE:A's SIWAN in a marriage of convenience.  

His wealthy and influential father brought in Jiyeon as an attempt to get Siwan's mind off Baek Jin Hee's character, who is considered an unworthy addition to the family.  When the two see each other in his father's office, Jiyeon tells Siwan, "Hello.  We last saw each other in Las Vegas, so it has already been two years."

EP 15: https://www.youtube.com/watch?v=aQYbhjlDHyw&feature=youtu.be
EP 16: http://www.youtube.com/watch?v=j6hFl8andU8
EP 17: http://www.youtube.com/watch?v=Om_VjOCqY4Y&feature=youtu.be
EP 18: http://www.youtube.com/watch?v=GxQ8iT4CMIA&feature=youtu.be&t=1m41s
EP 20: https://www.youtube.com/watch?v=7w9Fa5mug1s&feature=youtu.be
EP 21: http://www.youtube.com/watch?v=hjy5jpBvK0g&feature=youtu.be