In its early days, Australian television was highly regionalized, so while I've Got a Secret never aired on a national scale, at least four different versions were produced for individual stations in some of the country's major cities.
The earliest one aired in Melbourne on channel HSV-7, and was part of the very first day of television programming there on November 4, 1956. The host ("compere" was the word they used) was Eric Pearce, a British-born radio broadcaster who would become a famous Melbourne TV newsreader. The debut panel consisted of former Aussie footballer Jack Dyer, college French professor Olive Wykes, newspaper cartoonist John Frith, and radio personality Shirley Cecil. (Cecil had earlier been a panelist on the radio version of what Melbourne called What's Your Line?) The special guest on that first episode was a 21-year-old American actress and beauty queen ("Miss Hollywood 1956") named Jean Moorhead. This version appears to have aired until 1958, with a total of 63 episodes produced. TV presenter John Eden took over as host a little more than halfway through the run.
A version in Sydney on channel TEN-10 debuted on October 31, 1968 and ran until April 14, 1969, a span of only 5 1/2 months. it aired Thursdays at 7pm. Veteran TV host John Mahon compered the brief run (they really liked that word!), and panelists included actress Carol Raye, actor Peter Reynolds, swimmer Sue Costin and radio personality Bob Rogers. Costin, an aspiring actress, was only 25.
The four images below are from a show produced in Adelaide, on Australia's southern coast. This version aired on Adelaide's local ADS-7 station on Thursday nights at 7pm. These photos are from the early seventies. The host is Bob Francis, a popular radio personality. The panelist on the far left is British-born actress Ros Wood, and the gent next to her is Barry Ion, a former footballer (Australian Rules, of course) who enjoyed a successful second career in broadcasting in both Adelaide and Sydney.
Yet another version aired from 1965 until 1974 on channel QTQ-9 in Brisbane, the capital of Australia's Queensland territory on the continent's east coast. Newsreader Don Seccombe was the host of this one, and regular panelists included actress Babette Stephens, radio and TV personality Ron Cadee, actress and TV personality Joy Chambers (who would marry producer Reg Grundy in 1971), and TV presenter Russ Tyson. This version was an extremely popular series, winning the Logie Award (Australia's Emmy equivalent) as the most popular series in Queensland five times in a six-year span between 1968 and 1973.
The Adelaide and Brisbane versions, and possibly the Sydney one, were produced by Reg Grundy, a celebrated television figure in Australia despite the fact that most of his best work, and practically all of his early work, was not his own creation. Throughout the sixties and into the seventies, Grundy would regularly fly to New York, hole up in a hotel room, take careful notes on the game shows he would watch, then return home and recreate them for an Australian audience. By his own admission, in the early years he didn't even bother to secure the rights to the shows. That would change over time as copyright rules tightened and his empire grew. Still, to admiring viewers in his own country, Grundy appeared to be a genius when it came to dozens of game show formats that weren't his.
The clip below is not a full episode, but it is complete game from 1972 featuring The Bee Gees. The surviving video that featured this clip was itself an anniversary show looking back at Brisbane television history, so you'll see some unusual edits and "new" graphics identifying the panelists.