It’s been 65 years since TV viewers first met The Lennon Sisters, but when Kathy, Janet and Mimi Lennon take the stage today, magic happens. “We’re lucky that we still have our voices and can still fit into those beaded gowns, Janet, 74, exclusively tells Closer Weekly, on newsstands now. “We love working together and after all this time, we’re still best friends.”

America’s longest-surviving sister act has weathered many storms — most famously the murder of the girls’ father by a deranged fan in 1969 — but with love, unity and faith, they persevered. “The tragedy changed all of our lives, yet we came out knowing we had each other, we had Mom and we were blessed together,” says Kathy.

Growing up in Venice, California, the 11 Lennon children had no show business aspirations. But older sisters Dianne (DeeDee), Peggy, Kathy and Janet liked to harmonize and got their big break when Lawrence Welk’s son, who went to school with DeeDee, introduced them to his father. “I was 12 years old,” says Kathy, 77, who performed with her sisters on The Lawrence Welk Show for the next 13 years. “He was like a grandfather you loved but were a little afraid of!” she admits.

The girls had begun working on their own variety show, The Lennon Sisters Hour, in 1969 when a stalker who believed he was married to Peggy shot and killed their father, William. “Our mother was incredibly strong,” recalls Kathy. “And [singer] Andy Williams told us that we couldn’t let this man ruin our lives or our careers.”

Over the years, The Lennon Sisters have released 21 albums, including the career-spanning Lennon Sisters Ultimate Christmas Collection, received a star on the Hollywood Walk of Fame and entertained seven presidents. A documentary about their lives, The Lennon Sisters: Same Song, Separate Voices, is currently airing on PBS. Despite their success, Kathy and Janet say they are most proud of the closeness of their family. “We had a great childhood — we’d relive it all in a second,” says Janet. “But we always would rather be sisters than entertainers.”

— Reporting by Katie Bruno

For more on this story, pick up the latest issue of Closer magazine, on newsstands now.