joking apart/aside

(all) joking apart

In all seriousness; being frank for a moment. Primarily heard in UK. Just flew in from Denver, huh? Your arms must be tired! Joking apart, how was your trip out here? I give my brother a hard time for the gangly way he runs, but all joking apart, he's quite a remarkable athlete.
See also: apart, joke

(all) joking aside

In all seriousness; being frank for a moment. Just flew in from Denver, huh? Your arms must be tired! Joking aside, how was your trip out here? I give my brother a hard time for the gangly way he runs, but all joking aside, he's quite a remarkable athlete.
See also: aside, joke
Farlex Dictionary of Idioms.

(all) joking aside

 and (all) kidding aside
being serious for a moment; in all seriousness. I know I laugh at him but, joking aside, he's a very clever scientist. I know I threatened to leave and go round the world, but, joking aside, I do need a vacation.
See also: aside, joke
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

ˌjoking aˈpart/aˈside

(British English) used to show that you are now being serious after you have said something funny: No, but joking apart, do you think we should go and see if she’s OK?
See also: apart, aside, joke
Farlex Partner Idioms Dictionary
See also:
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  • (all) joking aside
  • joking aside
  • all joking aside
  • all kidding aside
  • kidding aside
  • (all) kidding aside
  • apart
  • aside
  • fussbudget