Mike Tindall signalled campmates to "back off" over Prince William conversation on I'm A Celeb

Mike Tindall made lots of headlines when it first emerged that he would be participating in this season's I'm a Celebrity... Get Me Out of Here!.

It was the first time a member of the royal family would be featured on the show, although other members of the family have appeared on wholesome reality shows such as A Berry Royal Christmas and The Repair Shop.

But just because Mike is participating in a super popular series doesn't mean he's going to reveal all the Firm's best-kept secrets.

The former rugby player even opted out of a fairly uncontroversial conversation about the royals during Tuesday's episode.

In one scene, Mike was filmed relaxing with footballer Jill Scott and singer Boy George. Jill asked how old the King was, then asked whether William was next in line to the throne, which George confirmed.

Jill then said: "I hope he's watching I'm a Celebrity... since he's mates with you, Mike."

George then cheekily remarked: "He's not watching because Mike's on it." This at least got a shocked gasp out of the man in question.

The singer then delivered his punchline: "He's watching it 'cause I'm on it."

For body language expert Judi James, Mike's decision not to say anything during this scene shows that he knows where the limits are when it comes to divulging information about the royals.

"His body language signals in the jungle suggest he is super-smart when it comes to switching to discretion mode," Judi told Metro.

Interestingly, Judi also believes that the personal stories Mike has told during the series have sounded "more scripted than off-the-cuff," perhaps a "pre-packed tidbit that ensured no one would accuse him of being tight-lipped during this TV appearance."

Judi further commented that, during this conversation, Mike was "very smart about tuning out when necessary but without looking precious or secretive."

She added: "Lying on his back he produces some very low response signals when Jill starts to ask about Charles’s age, making it look as though she’s just chatting to the group rather than quizzing Mike personally.

"When William is mentioned we get a rounding of the cheeks to suggest affection but still no 'bite' from Mike in terms of adding to the conversation after his small noise of agreement over Charles’s age. These are great passive responses to warn the rest of the group to back off but without looking or sounding reproving."

Judi also commented on Mike's comical gasp, saying he displayed "an open mouth of mock shock but still no active signals of communication to do anything but gently close down the subject."

She concluded: "It ends with laughter but we can still see the others testing Mike’s parameters and being politely shown when to back off."

If he ever writes a memoir, he could call it Mike Tindall: from pro athlete to pro secret-keeper. Just an idea.