The Sopranos star and her husband, baseball star Cutter Dykstra, invited Spider-Man to partake in the b-day festivities for Beau -- who turns three next Sunday -- and shared a heartwarming snapshot of the special day to Instagram.
"My little baby is not so little anymore," the 35-year-old actress captioned the cute pic. "Thank you to everyone that came out to celebrate Beau today!"
The party apparently included face painting, and easily the most epic superhero-themed birthday cake imaginable, including icons from both the DC and Marvel Universes.
Beau already started getting presents for his upcoming birthday last week, including a stylish punk-art portrait of Popeye -- a gift from Lance Bass and his husband, Michael Turchin -- which Sigler shared to Instagram on Friday.
"Thanks for the early bday present," she wrote in the caption. "At 3 years old , Beau will start his art collection :). We love you!!"
Sigler spoke with ET in February about her new husband, and how things have changed since exchanging vows. "We're four years into our relationship, so we didn't necessarily think it would be any different, but it is," she explained. "It's fun to say husband and wife. We're a unit. We're a team. We always have been, but now it's just even more official and real." Check out the video below to hear more.