Liev Schreiber Shares 'Corny Ritual' He Would Honor His Grandfather with Before Performances

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Liev Schreiber's connection to whiskey is deeply personal.

The actor, 55, who recently launched his own whiskey brand, Sláinte Irish Whiskey, which he created with co-founder Richard Davies, spoke with PEOPLE about what called him to venture into the spirits industry.

"I have a series of heavy, personal stories with whiskey," he says.

Years ago, his grandfather told him a story about whiskey that shaped some rituals early on in his career.  "They used to believe that, the reason that it's called spirits is because when you drank it, the spirit of the bottle would possess the person and that's why they became drunk," he says.

Since Schreiber wasn't close with his father, he says he had a very strong bond with his grandfather and would pay homage to him with a "corny ritual" during his theater days.

"I had this ritual where I would toast my grandfather before I went on stage, and I was doing these big Shakespearean tragedy plays. So it was like I was very much into this idea of being possessed by that tiny sip of Irish whiskey and having him help me get through my stage fright and go out on stage with something beyond my normal banal humanness," he says.

"It was pretty powerful until I started getting too drunk," he continues, laughing. "So I had to switch and it became red wine because I was so superstitious. I couldn't stop toasting my grandfather."

RELATED: Liev Schreiber Helps Cook for Ukrainian Refugees in Poland for Passover: 'Happy Pesach'

Jake Chessum/Sláinte Irish Whiskey

Whiskey also played a key role when Schreiber was in college and his father came back into his life after his parents' "acrimonious divorce" when he was a child.

"He came to see me with a bottle of whiskey, and the two of us drank almost an entire bottle of whiskey and…he talked mostly and cried a lot about the time that we had been apart and what had been going on in his head," he recalls. "And so at that point in my life, I was not a big drinker, but I was introduced to this spirit."

Sláinte, which translates to "good health," is a term of unity that Schreiber finds so crucial to his connection to whiskey and, in turn, his own liquor company.

"The spirit of that idea really works for me. It really is trying to bring people together. And it really does do that," he says. "And it really owns a warm place in my memory because of my father and my grandfather."

RELATED: José Andrés Considers Himself 'One More Volunteer' In World Central Kitchen Efforts

Liev Schreiber Instagram

The Irish whiskey isn't just about drinking good, but doing good as well. All funds from Sláinte's limited edition, 18-year-old bottle ($499 each) will go towards Schreiber's humanitarian organization, BlueCheck Ukraine, which offers assistance to those in areas of conflict.

"Now more than ever we've got to be supporting them with humanitarian aid," he says. The Ray Donovan star has been to Ukraine three times since Russia started the war in February. He recounts the moment he knew he needed to mobilize humanitarian support.

"I think the biggest impact was before I went to Ukraine. I was sitting on the couch with my kids watching these middle-aged men who looked a lot like me, big-boned, balding, middle-aged guys who definitely didn't look like they were soldiers, saying goodbye to their families and getting on buses," he says.

"And you could see in these guys' faces and you could certainly see in their children's faces that they had no idea whether they were going to ever see them again. And I'm sitting there on the couch with my kids watching CNN thinking, 'Could I do that?' 'Would I have the kind of courage it took to do that?'"

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After cooking a Passover meal for refugees in Poland through José Andrés' World Central Kitchen, Schreiber says the chef helped him get connected on the ground to help funnel aid to NGOs in Ukraine.

He's met with President Volodymyr Zelenskyy, and BlueCheck Ukraine has even helped the leader set up his own global aid initiative, United24.

"I'm really impressed by his courage. I'm really impressed by his conviction, his savvy," says Schreiber. "Zelenskyy stood his ground. He said, 'I'm going to stand by my people.'"

As the winter months loom, Schreiber says global support for Ukraine is even more important, another reminder of why he decided to build a business based on bringing people together and helping those in need.

"At this point in my life, to be able to pivot my fame or celebrity into something that might matter to my kids in five or 10 years," he says, "I'm wildly grateful for that."