Almost 20 million television viewers tuned in to watch the ninth Democratic debate on Wednesday, according to Nielsen Fast National Data.
It was the first debate to feature former New York Mayor Mike Bloomberg.
Six rivals — Bloomberg, former Vice President Joe Biden, Sens. Bernie Sanders, I-Vt., Elizabeth Warren, D-Mass., and Amy Klobuchar, D-Minn., and former South Bend, Indiana, Mayor Pete Buttigieg — spent two hours Wednesday night duking it out at the Paris Las Vegas Hotel & Casino.
It was the most pugnacious debate so far and came three days before the crucial Nevada caucuses.
Almost every Democratic candidate took a swing at the debate newcomer.
Bloomberg, who jumped into the race in November and is not on the ballot in Nevada, did not qualify for previous debates because his campaign does not take contributions and so it didn't meet donor thresholds. The Democratic National Committee dropped the donor requirement in January, paving the way for Bloomberg to join the fray.
Bloomberg's addition to the stage on Wednesday may have contributed to the surge; television viewers inundated by his campaign ad blitz might have tuned in to see how he would fare in a live setting pitted against his rivals.
In addition to the nearly 20 million who caught the debate that aired on NBC News and MSNBC, 13.5 million viewers watched the debate online over a livestream.
The first Democratic debate in June drew 18.1 million viewers and was also hosted by NBC News and MSNBC.
Viewership tapered off following the first debate, with the others drawing less than 10 million views each night, according to Deadline.
NBC and MSNBC are units of Comcast, which also owns CNBC.