June Lockhart Remembered by TV Sons from 'Lassie' & 'Lost in Space'

June Lockhart was a beloved actress — the last of the black-and-white TV show moms — and no one appreciated her more than her peers.

After it was announced Saturday that Lockhart had died of natural causes at the age of 100 on Thursday, her two most famous TV sons remembered her fondly.

Her "Lassie" co-star Jon Provost, 75, who played Timmy on 250 episodes of the series from 1957-1964, remembered Lockhart, who played his mom Ruth on the show from 1958-1964, wrote on Facebook, "She truly was my second mother."

He then relayed a touching story, going on, "I remember some advice June gave me early on. We were on the set and I was misbehaving a bit, being a little mischievous. June took me aside, and very firmly explained to me that we were professionals and that we had a job to do. She told me that I was a young boy playing a young boy, but that one day I would be an adult, playing an adult like her."

He wrapped up with a heartfelt thought: "June was a true professional, with a kind heart and an open mind."

She was also remembered warmly by TV icon Billy Mumy, 71, who played her son Will on "Lost in Space" from 1965-1968. Mumy, whose character inspired the eternally familiar catchphrase, "Danger, Will Robinsin!," wrote on Facebook of the woman who played his mom Maureen, "Goodbye to the brilliant June Lockhart. A one of a kind, talented, nurturing, adventurous, and non compromising Lady. She did it her way."

Mumy humorously ended with, "June will always be one of my very favorite moms," before observing, "100 years here. Wow! R.I.P."