A DAD has described the “shocking” moment he found out he'd fathered 25 kids with sperm he donated for “quick cash”.

Peter Ellenstein, 57 – who has dubbed himself “The Sperminator” - sold his sperm to make ends meet while struggling to get by as an aspiring actor in Los Angeles the 1980s and 1990s.

But around 30 years later he was tracked down by dozens of children he had helped to father.

The divorcee exclusively revealed his incredible story to Sun Online last month – and said he believes he could have hundreds more kids he doesn’t know about.

And today he appeared on Good Morning Britain to describe the life-changing moment he was first contacted by one of his offspring.

Peter – who admitted pals used to joke that he probably had loads of children – said he was nevertheless shocked when he got a message from daughter Rachael.

He said: “I was sitting at breakfast one day with a friend of mine when all of a sudden Rachel’s message popped up and my face blanched and my friend said, ‘What is it?

“I handed him the phone and he knew the story and he just burst out laughing.

“It was an enormous shock and it took me I think about eight hours before I responded to her message at all.

“And in the mean time I called up the California Cryo Bank which was one of the places I donated and said, ‘How could someone have found me?’

“And I texted my brother and sister and my wife at the time and said, ‘Oh my God, what do I do?’”

Rachel had managed to track her father down after years of searching led her to match her DNA to 11 donor siblings, Sun Online previously revealed.

Pooling together different information they had been given by their parents, they figured out that their dad was an actor from Los Angeles and they knew his name.

She put the name into a movie database and found a “Peter Ellenstein”, then managed to track him down on Facebook.

After agreeing to meet Rachel, the theatre producer said another 12 kids came forward over the next year.

He revealed he’s now discovered 25 children – 20 of which he’s met so far.

But despite his initial misgivings, Peter said learning about his unconventional brood has made him happier than ever.

He told GMB: “For me it was really profound and shocking.

“I felt so much that I was looking back at a part of myself, and it opened up an entirely different part of my heart and my brain.

“If I was told a year and a half ago that this was going to happen, and it was going to be a good thing I would have said no, no thank you, I don't want that to happen.

“But having had it happen, it's the best thing that's ever happened to me in that it opened me up to a whole new experience of what being alive is.”