The network brought the popular game show back to prime time to celebrate its 10th anniversary. Celebrity guests have been invited to answer one question in hopes of earning cash for his or her favorite charity.
The evening episodes, which feature original "Millionaire" host Regis Philbin, have been running since Aug. 9 and are to conclude Sunday.
The evening game show began in 1999, with Philbin as host, and ran for several years before becoming a 5-episode-a-week, daytime syndicated series, starring Meredith Vieira.
Country music star Wynonna appeared on Tuesday's prime time episode and played for Backpack Mission Ministries, while journalist, newscaster and author Gwen Ifill was the expert for the episode's "Ask the Expert" lifeline.
Rapper Snoop Dogg, playing for the Snoop Dogg Youth Football League, is to be the celebrity guest on Wednesday night's installment with "Jeopardy!" winner Ken Jennings serving as expert.
NBA star Steve Nash, playing for The Steve Nash Foundation, is expected to appear on Thursday's show with NPR's Mo Rocca helping out as expert and a surprise guest is to drop by Sunday's finale when Bill Nye the Science Guy will be the expert, ABC said.