Over the nine months of his presidential campaign, Donald Trump has yet to step to a podium and read from a script. That changes Monday, when he is set to address more than 18,000 people attending the annual American Israel Public Affairs Committee conference in Washington.

He’s also looking to surprise the crowd with something else: substance.

“He has taken input from a number of very significant Jewish influences who have reaffirmed to him the importance of this particular speech,” according to a source close to Trump’s campaign. “He is taking it very seriously.”