Melissa McCarthy and Kristen Wiig visited a children's hospital in full 'Ghostbusters' garb.

The cast of the upcoming Ghostbusters movie stopped by Floating Hospital for Children at Tufts Medical Center, but they weren't there to bust ghosts.

The Ghostbusters cast (from left): Leslie Jones, Kate McKinnon, Kristen Wiig, and Melissa McCarthy. Photo courtesy of Floating Hospital for Children at Tufts Medical Center.

The actors were much more focused on putting smiles on patients' faces.

While of course they don't fight ghosts in real life, actors Kristen Wiig, Melissa McCarthy, Leslie Jones, and Kate McKinnon — who all showed up to the Boston hospital in full Ghostbuster uniform — play the part in their upcoming movie, "Ghostbusters," which is set to release in theaters in July 2016.

' Photo courtesy of Floating Hospital for Children at Tufts Medical Center.

The actors showed up after the patients, knowing the movie was filming nearby, put signs up in their windows that spelled out, "Who ya gonna call?"

Photo courtesy of Floating Hospital for Children at Tufts Medical Center.

(The answer is, of course, "Ghostbusters!")

The signs worked, and the hospital was thrilled to welcome the cast to visit the patients.

"We got the call Saturday morning to ask if they could come over in between shoots," Julie Jette, the hospital's director of media relations and publications, explained to Upworthy. "We were thrilled they could make it!"

Jette noted that the cast was careful to tailor the experience to each child, depending on their age and how they were feeling that particular day.

Photo courtesy of Floating Hospital for Children at Tufts Medical Center.

Although nothing too spooky went down, it didn't make the day any less cool.

"The cast did an amazing job making the visit fun," Jette said. "We had several patients and parents come to us afterwards to say what a difference the visit made to them."

Photo courtesy of Floating Hospital for Children at Tufts Medical Center.

"There were two children who were being discharged from the hospital ... who said it was a wonderful way to conclude their time here," Jette said. "It sent them off on a really high note."

As if I needed another reason to see "Ghostbusters," I can now add, "Its hilarious, ghost-hunting cast also makes deserving kids happy," to my list.

Remind me: How soon is too soon to buy a movie ticket in advance?