Washington (CNN)Democratic presidential candidate Beto O'Rourke will speak at a CNN town hall at 10 p.m. ET on Tuesday, May 21.

CNN's Dana Bash will moderate the town hall from Drake University in Des Moines, Iowa.

O'Rourke, a former Texas congressman who lost a high-profile Senate race to incumbent Sen. Ted Cruz last year, announced his long-anticipated presidential campaign in March.

He enjoyed a strong launch, raising $6.1 million on his first day in the race and calling for the national hierarchy "to be broken apart" at his first rally in his hometown of El Paso. But a CNN poll last month of Democratic or Democratic-leaning independent voters shows O'Rourke in fifth place with 6% -- a drop from 13% in the previous poll.