The Duke of Cambridge was transformed into a samurai warlord when he visited the set of a long-running Japanese drama.

Wearing a glittering helmet, regal red and gold tunic and carrying a replica samurai sword William looked every inch a formidable ruler.

He was transformed into Toyotomi Hideyoshi, the Japanese warlord who unified his country in the 16th century, during a tour of the Tokyo studios where the Sunday night historical drama Taiga is filmed.

Now in its 54th series, it features famous characters from Japanese history but changes the period for the action every year with the current series called Hana Moyu or Ardent Flower.

When William first arrived at the studios of Japan’s public broadcaster NHK (Nippon Hoso Kyokai) which makes the show, he was greeted by a long line of actors dressed as soldiers.

He asked one of the senior staff: “Is it a show like EastEnders?” before being taken on to the set that depicted a chaya or tea house, used by samurai as a members’ club, complete with geisha.

As staff put the helmet on his head, the Duke joked: “I feel there should be a sword in my hand as well.” And when he was told actors wore the costume and heavy armour for many hours he replied: “Not particularly easy to go for a coffee break.”

When they were finished he looked into a mirror and asked his entourage: “How do I look?” before adding: “I feel ready for action.”

Before dressing up he watched three geisha actresses dance, while another Maki Shiran, 23, played a three-stringed guitar-like instrument called a shamisen.

At the end of the performance he tried strumming it himself and said “it’s a wonderful noise”, as he plucked the silk strings with a large plectrum, which he was told was made of ivory.

The Duke, who will be travelling to China, where he will speak out against the ivory trade, said with a wry smile: “Oh, is it?”

Mao Inoue, the female star of Hana Moyu, who plays a character called Humi Sugi, presented the Duke with a bouquet of flowers and a hand-made wooden toy for Prince George.

In the hair and make-up department William dissolved into a fit of giggles when Tim Hitchens, Britain’s ambassador to Japan, put on a samurai wig.

The former Queen’s deputy private secretary was game for a laugh and sat in a chair as Kahame Mimura, head of hair dressing and wigs, covered his scalp with a piece of cloth before fitting the hairpiece.

The Duke had considered wearing the wig, made with real hair and slicked back into a tiny ponytail, but said: “If I put this on my brother would never let me forget it – I seriously can’t.”

After the transformation of the senior diplomat William could not resist poking fun and told him through laughter: “This is going straight on to the Foreign Office website – brilliant.”

The ambassador stood up and flexed out his arms as if he were a sumo wrestler and the Duke quipped: “A bit more weight and you would be sorted, get the sumo wrestling going – impressive, a good look.”

Later the mood was more serious in NHK’s newsroom, where the Duke watched a three-minute film showing how the station covered the devastating 2011 earthquake and tsunami which triggered the meltdown at the Fukushima Daiichi nuclear plant.

He was visibly moved as he watched footage of homes, roads and cars being swept inland and fields being swallowed up by the 10-metre high tidal wave.

The harrowing images were filmed by one of NHK’s 15 helicopters, which took off immediately after the earthquake and was guided by staff in the newsroom.

The broadcaster was set up in the wake of the Great Kanto Earthquake in 1923, when it was realised accurate and prompt information protects lives.

William was also shown how NHK is alerted whenever the country experiences anything over a magnitude three tremor.

Newsreaders interrupt all of the station’s TV and radio programmes to give an emergency tsunami warning after a quake of magnitude five or more.

The warning, which is broadcast in several different languages, says: “This is a tsunami warning, please move to high ground.”

William listened intently as the station’s president Katsutomo Momii explained the system to him.

He was then shown how NHK staff practise the warning drill every night and he got the chance play anchorman as he took a seat in the news studio.

He said: “I feel like I should be doing interviews and asking the questions.”

Inspecting the bank of controls used to launch the early warning system, he asked: “What happens if I press the red tsunami button now?”

Thankfully the Duke was told it was just a simulation and the warning would not be going live.

Looking at the autocue used by presenters to warn viewers, he joked: “This is how the BBC do it then, it’s cheating.”

As he left the building, William met NHK’s mascot Domo-Kun and he laughed as it bowed to him and offered his hand to shake.