David Tennant trolls his son during a House of the Dragon fan meet and greet event

David Tennant has continued an old family tradition at a comic book convention: shaming his fellow family members at a meet and greet.

His son, House of the Dragon star Ty Tennant, suffered through his turn at the hilarious tradition at London Comic Con over the weekend.

Ty, who played a young Prince Aegon Targaryen in the Game of Thrones spinoff series, was signing headshots and meeting fans when his dad appeared behind him with a sign that read: "He's not that special."

Ty's mum Georgia Tennant shared the snap to social media, which showed the actor not looking too thrilled about the signage.

On its own, it looks like a dad taking the mickey out of his son.

But if you dig a bit deeper, you'll find that the very same prank has been played on David Tennant before.

The Doctor Who star received the same treatment from his father-in-law, actor Peter Davison, at Wales Comic Con back in April.

Davidson played the fifth Doctor, whereas Tennant played the 10th and 14th regenerations.

Davidson stood behind Tennant holding up a sign that also read: "He's not that special."

The same post also showed Davidson standing in front of Welsh actor Michael Sheen with a different sign that read: "Now he is special."

Tennant's wife also shared another social media snap of her dad from earlier in the day with a quote from her famous father.

"Here I am protesting in front of the half mile queue for your husband," she wrote on Twitter, quoting her dad.

And it turns out that fans loved Davidson's jape, with the 'not special' sign catching on with one little girl turning into a comic book convention costume.

The humour of Tennant's dig at his son Ty was not lost on fans, with many taking to social media to join in on the ribbing.

One Twitter user said: "Like father, like son(-in-law)."

Another added with laughing emojis: "What a lovely family tradition."

Another user quipped "Everybody needs to know how David can't even tease Ty without making a lovely hidden message."

Another just pointed out how similar Ty looks alongside his own famous dad.

One user said: "Wow! Ty Tennant definitely is a bit of a mini-me" of Dad, isn't he?"