Wiktionary
adv. (context speech act idiomatic English) (non-gloss definition: Used to attempt to make a serious point in a jocular conversation.) alt. (context speech act idiomatic English) (non-gloss definition: Used to attempt to make a serious point in a jocular conversation.)
Wikipedia
Kidding Aside (The British Childfree Association) was founded in 2000 and exists in order to campaign for the rights of British childfree people. It is thought to be the first politically active childfree movement in the world and strives to introduce the childfree voice into relevant British political debate. It also works to promote the childfree lifestyle as a legitimate and equal alternative to parenthood, and campaigns for equality of opportunity for childfree people in employment and with regard to UK tax legislation. In addition to the voluntary childfree, the issues Kidding Aside speaks on also affect the lives of those who are involutarily childfree.
Usage examples of "kidding aside".
But you do know, don't you, all kidding aside, that I wouldn't think any less of you even if you were way off base here?
Yet, all my kidding aside, you had to handle each one of these routine assignments as though it could blow up in your face.
But, Chrisall kidding aside, and bushels of mazel tov what am I going to doooo?
All kidding aside, it'd be better for you not to stay on here any longer than the storm.