Both SNSD and DBSK maknae had taken some pictures together during their pre debut (that is during the SMART CF)

When DBSK attended a Japanese Talk Show, they mentioned how they have known SNSD for a long time. They also mentioned the maknae, Seohyun has now turns into a charming woman.

On KMW Goggle, Changmin received a Keroro doll from someone. Because he knew how much Seohyun likes Keroro, Changmin passed the Keroro to Seohyun (that caused Kyuhyun to glare at them)

During the ending of a concert, Changmin held Seohyun hand at the end of the concert to give the audiences a big bow.

On 26th Nov 2012 at an airport, both Changmin and Seohyun was spotted wearing the same style when came back to Korea after finished their concert. They indeed have the same taste in fashion. 

During SMTown I AM Showcase, Changmin (and Kyuhyun) was seen glaring at Seohyun when she was talking (just like EXO K Suho)

On JBJ Talk Show, Changmin always gave full attention to Seohyun. Seohyun admitted that she is the same as Changmin because she likes to nag to the unnie like how Changmin does to Yunho. After Leeteuk revealed that he is over-protective of Seohyun and wanted Seohyun to stay the way she is, Changmin advised her the opposite. He wished so that Seohyun would hurry finding a boyfriend or else she gonna ended up with a weird person like Heechul. Seohyun surprised everyone especially Changmin when she revealed that she has an ideal type in SM. But cause a big dissapointment  when it turns out to be SNSD choreographer, Jaewon. However, when Changmin was selected as the third ideal type after Leeteuk, he couldn't hide his happiness and started clapping.

When the MC asked how they would wake their spouse up if they are sleeping, Changmin said that he wanted to receive a kiss on his eyes while Seohyun said that she would whispered his spouse's name into his ear.

During dinner, Changmin was busy grilling the barbeque. Seohyun showed care for Changmin when she asked Tiffany to feed him or not. When Yunho wanted to feed Changmin, he refused. But when Seohyun was the one to feed him, he quickly ate it.

Changmin also had attended Seohyun's birthday part during the end of June. If we looked at again, all Seohyun's fanboys attended her party (Kyuhyun, Changmin, Jinwoon, Leeteuk, Eunhyuk) except Minho :((

During MBC Gayo Daejun, Shinee's Jonghyun grabbed Changmin's hand to talk with him but Changmin completely ignored Jonghyun and went ahead to Seohyun. He said something to Seohyun and they both smiled.

During SMTown Press Conference in Singapore, Yunho stared at Seohyun who was sitting behind. When Seohyun turned at Yunho, he gave her a thumb telling her to do well. Seohyun then smiled at him. Both Donghae and Suho noticed them. Donghae pretended not to care while Suho continued to smile at Seobaby.

Lately, Seohyun and Yunho had been spotted together at the airport after finished the SMTown Concert. Yunho patted on Seohyun's shoulder and even grabbed her wrist. They looks really close. Well, Yunho did say that his ideal type is tall girl with long hair.

Besides, both Yunho and Seohyun had participate in a photoshot before.

Now, let us look at Seohyun and DBSK

Yunho grabbed Seohyun's shoulder while Changmin placed his head on Seohyun's lap while holding her hand

[Side note] If you realize, all Kyu-line is fanboying Seohyun xD