It's Sheldon in drag! Big Bang Theory's Jim Parsons wears fishnet tights to perform Rocky Horror song with cast

He's famous for playing uptight and geeky Sheldon Cooper on American sitcom The Big Bang Theory. But Jim Parson played a scientist of a different kind on Wednesday as he took part in a stage musical for charity. The 39-year-old actor wore black lingerie with a curly wig and fishnet stockings held up by suspenders while backstage at the 21st Annual A Night at Sardi's to benefit the Alzheimer's Association. Scroll down to view video...

In costume: Jim Parsons, left, and Kaley Cuoco posed on stage at the 21st Annual A Night at Sardi's to benefit the Alzheimer's Association at the Beverly Hilton Hotel on Wednesday

Run for her money: He wore fishnet stocking and suspenders with a bustier while she donned a maid's dress

Like ladies: Actors Steven Weber, left, and Jim both explored their feminine sides

Tongue-in-cheek: Actresses Emmy Rossum, left, and Kaley had fun at the star-studded gathering During the gathering held at the Beverly Hilton Hotel in California, he posed next to his blonde bombshell co-star Kaley Cuoco in his bustier and high heel shoes. Jim – who last year publicly came out as gay - played the iconic role of Dr Frank-N-Furter while 27-year-old Kaley took on the part of Janet Weiss. Other recognisable faces from the programme included Johnny Galecki, Mayim Bialik, Simon Helberg, Kunal Nayyar and Melissa Rauch, who donned more interesting attire featuring leather and studs as well as sequins. According to Variety Johnny quipped at one point to guests: ‘The more you drink, the better I’ll sound.’ The group were performing a number from the Rocky Horror Show and Kaley showed they were very much in the spirit to raise money as she slid along the floor to give her best effort.

In the spirit of things: Johnny Galecki, a guest, and actors Kaley Cuoco, Kunal Nayyar and Linda Hart perform on stage

Let's do the Time Warp: The group gathered together to do a dance for the Best of Broadway celebration

In character: Mayim Bialik, left, and Simon Helberg dressed up for The Rocky Horror show track

After stealing the show with their rendition of Time Warp they took snaps with other famous faces contributing to the cause. Kaley was spotted with actress and musician Emmy Rossum while Jim posed with actor Steven Weber. Prior to taking part in The Best of Broadway production, the cast appeared in the photo area in their most glamorous get up.

Red carpet glamour: Actors Kaley Cuoco and Johnny Galecki posed together before the evening

On-screen family: Kunal Nayyar, Melissa Rauch, Jim Parsons, Mayim Bialik and Mitch Hurwitz looked far from their appearances on stage and TV