"The Big Bang Theory" ended its ninth season on a cliffhanger — one that could potentially change Sheldon and Leonard's relationship. And before fans can find out the truth, they will have to wait for a while as the announcement of season 10's premiere date hasn't been made yet.

Season 9's final episode saw families gathered together. Leonard (Johnny Galecki) and Penny (Kaley Cuoco) held a second private ceremony as the latter promised to Beverly (Christine Baranski), the former's mother. Beverly was joined by Leonard's highly anticipated father, Alfred (Judd Hirsch), whom he had invited without his mother's knowledge — an action that angered her.

Leonard's parents were clearly not friendly towards each other after the divorce, especially since she was distant and he had an affair. But they weren't the only ones there to attend the private ceremony. Sheldon's mother, Mary (Laurie Metcalf), was also present.

Things started to get weird when Alfred and Mary hit it off, even though he didn't share her faith. At dinner, the two found themselves the targets of Beverly. As a result, they left early and headed to their respective hotels, which turned out to be the same. Mary then joined Alfred for a nightcap after he asked her.

The episode was left open-ended, with it seemingly pointing towards a hookup between the two. However, the truth is uncertain.

Executive producer Steve Molaro offered up his two cents on the matter when he was interviewed by Entertainment Weekly. However, he was careful not to reveal anything juicy.

"I don't know what happened. I know they were getting along quite well, and left to go to the same hotel for a nightcap, and turned off their phones. The details of exactly what happened, if we even ever find out all the details, will be left for the season premiere of season 10," he teased.

Additionally, Molaro revealed that, regardless of the persistent rumor that season 10 will be their last, he's not looking at it as the end.