joking aside

joking aside или joking apart  {v. phr.},  {informal}

Без дураков, без преувеличения: серьезно.

Joking aside, although the conditions were not very comfortable, we had a wonderful time.

Joking apart, there must have been over a hundred people in the room.

Син.:

кроме шуток, (отставив) шутки в сторону