Jennifer Hudson — who is set to star in the upcoming movie version of “Cats” — wowed the crowd with a performance at the Rainbow Room this week for the Alzheimer’s Association Fall Benefit — Rita Hayworth Gala.

We hear she sang a number of songs, including “Hallelujah,” noting it’s her favorite tune to perform.

Hayworth’s daughter, Princess Yasmin Aga Khan, who founded the event, made a toast, telling her guests, “my mother would be proud of our collective determination in the fight against Alzheimer’s.”

At the event were Peter Thomas Roth, Jay McInerney, designer Naeem Khan and Margo and John Catsimatidis.

Hudson will star as the lead in the upcoming star-studded Aretha Franklin biopic, “Respect,” along with recently named co-stars Forest Whitaker, Marlon Wayans, Marc Maron, Tate Donovan and Tituss Burgess, along with Mary J. Blige and Audra McDonald. Tony nominees Saycon Sengbloh and Hailey Kilgore will also star.