India, April 16 -- The Big Bang Theory stars Kaley Cuoco and Johnny Galecki, who dated during the early seasons of the show are together again. Before you jump to any conclusions, read on to know what the is reunion all about.

(Also read: Weird and beautiful: Jim Parsons on reprising 'The Big Bang Theory' character in 'Young Sheldon')

The former couple came together to star in an advertisement for the Royal kingdom mobile app. Kaley took to Instagram and posted the hilarious ad which surprised the fans.

Kaley wrote a note with the post that read, "Game Night with @sanctionedjohnnygalecki just levelled up thanks to @royalkingdom".

Johnny also posted the ad and wrote, "Game night with @kaleycuoco just got a serious upgrade thanks to @ro...