Collins was asked to share her memories of the Dot Cotton star, and joked that it was tricky on breakfast television as Brown was "a very naughty lady".
Read more: Tributes pour in for soap legend June Brown
She then recalled that the late screen legend took her fitness quite seriously.
"She was just really funny," she said.
"Somebody reminded me, once in the EastEnders canteen when I first started, she was obsessed with fitness, June.
"People don’t really know that. She really was. She was actually really quite healthy even though she smoked.
"She used to do her pelvic floors on the trolley in the canteen at the BBC. That’s all I’m saying!"
Brown was one of the original stars of the BBC soap, which launched in 1985.
She left in 2020.
Announcing that she had passed away, her family said in a statement: "We are deeply saddened to announce our beloved mother, June, passed away very peacefully at her home in Surrey on Sunday evening, with her family by her side.
"We would kindly ask that our privacy is respected at this very difficult time."
A statement released by the soap said: “There are not enough words to describe how much June was loved and adored by everyone at EastEnders, her loving warmth, wit and great humour will never be forgotten.
Read more: Dot Cotton's most memorable storylines
"June created one of the most iconic characters in Dot Cotton, not just in soap but in British television, and having appeared in 2884 episodes, June’s remarkable performances created some of EastEnders finest moments."
Watch: John Altman pays tribute to screen mum June Brown