The film, which is a sequel of hit 2011 comedy drama, will hit theatres on June 7.
"'Yamla Pagla Deewana 2' from its promo and ads, is a scream!! Wishing Dharamji, Sunny and Bobby all well deserved success," Bachchan, 70, posted on twitter.
Dharmendra, 77, who will reprise his conman act in the Sangeeth Sivan directed film, also called up Bachchan to thank him for praising them.
"Dharam ji calls to thank me for YPD2 tweet ! Greatness is bestowed on those who have great hearts, and Dharam ji has tons of it," Bachchan added.