Morgan Freeman 's soothing low voice is one of his trademarks, so it was extrafunny when the actor took part in an interview on the Tonight Show Starring Jimmy Fallon while sucking on helium. "I really shouldn't be doing this," Morgan said. "It's very undignified." Of course, Morgan's dramatic voice change sent host Jimmy Fallon into a fit of giggles, which just made the whole stunt all the more silly. Of course, this isn't the first time that Morgan has talked while on helium , but the bit was still fun. Watch the interview above.