just kidding... but seriously 

When someone says something that they want to admit but not really but they still think it and they kind of want you to know that they are serious

Freddie: dude that girl is hott... I want to hit that shit
Chris: dude that's my sister
Freddie: I'm just kidding... but seriously

just kidding... but seriously by Chirs Irving October 17, 2006

LOL jk but seriously though 

You say LOL jk but seriously though after you say something offensive to someone or about something.

Only say this on the internet or texting. If you want to say it in real life, say "Haha. Just kidding. . but seriously though".

*It can be reduced to: LOL jk but seriously

Example 1

Lily: Dude, Sally needs to stop making out with everyone.
Mary: I know right! She's such a whore. LOL jk but seriously though.

Example 2
(John is driving his girlfriend's bug)
Bill: Hey, John, can you give me a ride?
John: Sure, man!
(they walk to John's car)
Bill: Whoa. Dude, that is one fruity car. Haha just kidding. . .but seriously though.
John:. . . that's my girlfriends car. .

LOL jk but seriously though by Lily Snape July 1, 2011

but seriously 

This term is usually used after saying a non-intended humorous quote or phrase.

This term can also be used to put a serious twist on your joke, and frequently intensifies the situation.

It is also used to make a joke more humorous, this is called backing-up(usually used after your not-so-funny-joke)

#1:
Person 1: Yeh i got a vest the other day!
Group: HaHahahAhAh
Person 1: but seriously

#2:
Person 1: I've got a vest....jokes....but seriously
Group: HaHahahAhAh

#3:
Person 1: Vest are only for 'homos'
Group: *cough*
Person 1: but seriously!
Group: HaHahahAhAh

but seriously by Semaj R. Llih and Samoht H. Nosreme December 13, 2008

… but seriously 

An album by Phil collins

person 1 : … but seriously
person 2 : Phil Collins?
person 1: I uh-

… but seriously by _____chaAzzA June 30, 2021