Until last November, Jack Wagner had never met his daughter.
Now reunited, the actor and the 23-year-old woman who had been put up for adoption as an infant will continue their blossoming relationship at a charity event next month – and at Dancing with the Stars.
"I get so emotional," the actor, 52, tells PEOPLE as he choked back tears during break in Dancing rehearsals with pro partner Anna Trebunskaya. "She's the new light in my life, as well as my sons, and I'm really grateful to her for having the courage to find me."
Wagner had been told about the baby by her mother after the child was put up for adoption. He hired a lawyer but was advised his legal options were limited and he never knew for certain if the mother – with whom he only had a brief relationship – was telling the truth.
Now a dance instructor in Florida, the woman, named Kerry (she hasn't released her surname), went on a search for her birth parents that led her to Wagner, who also has two sons, ages 17 and 21 with ex-wife Kristina.
Kerry will join him along with other family members on April 16 during his Celebrity Golf Classic benefiting The Leukemia & Lymphoma Society (he lost his father to multiple myeloma and his brother has been fighting leukemia).
And Wagner advances far enough on Dancing with the Stars, which begins Monday, she'll be cheering him on from the audience.