Sylvester Stallone makes his first public appearance since son’s death

Although he's grieving the loss of his son and dealing with another family crisis, Sylvester Stallone put on a brave face Thursday to make a surprise appearance at the Paris premiere of "The Expendables 2."

It had been widely reported that Stallone — who buried his son Sage Moonblood Stallone last month — would not participate in the promotion of his latest action film, for which he also wrote the screenplay. However, the 66-year-old showed up at Le Grand Rex theater — flanked by his co-stars Jean-Claude Van Damme, Arnold Schwarzenegger, Jason Statham, and Dolph Lundgren — for the event. Dressed in a gray suit, he appeared somber at first, but livened up soon after. He even was playful for photographers, jokingly giving Lundgren a left hook and flashing a thumbs-up.

[Related: Schwarzenegger and Stallone negotiated 'Expendables' at the hairdresser]

Shortly after, Stallone appeared with his cast again at a photo call for the movie. Wearing jeans and linen blazer, he appeared much more at ease, smiling and laughing with his friends.

Stallone skipped the promotion of the film in the United States so he could take a European vacation with his wife, Jennifer Flavin, and their three daughters. Lundgren said Stallone was greatly missed but understood that he needed time away to grieve. "Something like that is so severe. You can't really do anything," Lundgren told reporters. "I sent him a handwritten note. I contributed to a charity for his kid. He knows we're thinking about him. He knows us. He knows our prayers go out to him. But what are you going to do? I have two kids. And all you can do is hug your kids and go thank God it didn't happen to you."

On Friday, a new report revealed that Stallone's personal heartache isn't limited to the loss of his son. His half-sister, Toni Ann Filiti, is in critical condition at UCLA hospital, suffering from stage 4 lung cancer as well as liver cancer, which has spread to her brain. Their 90-year-old mother, Jackie Stallone, told the New York Post, "I am doing terrible after having my grandson go, then my daughter [critical] at 48 years old. It isn't easy. ... The doctors don't think she will improve. What can you do? They have done everything. ... What we need is a miracle."

[Related: Sage Stallone, eldest son of Sylvester Stallone, found dead at 36]

She added that her famous offspring was helping Filiti's son, Edmund, from afar. "Sly is in Europe. My grandson says Sylvester has been very helpful to him. Sylvester has been his morale booster."

Meanwhile, the investigation into the death of Sage continues. Stallone and his ex-wife, Sasha Czack, were devastated when their 36-year-old son was found dead in his Los Angeles home on July 13. According to the L.A. County Coroner, there were several bottles of pills in his room. A toxicology report is pending.

"The Expendables 2" will be in theaters August 17.