Anthony Joshua has revealed the intensity of the drug-testing he has faced in the build-up to Saturday's fight with Dominic Breazeale.

The IBF heavyweight champion makes the first defence of his title at London's 02 Arena less than three months after winning it at the same venue by stopping Charles Martin.

It is the latest stage of a challenging schedule that began when he signed to fight Dillian Whyte last December, and one in which his freedom has been further restricted by the demands placed on him by UK Anti-Doping.

"The two testers turned up at the place I was staying in Sheffield and wanted a urine sample there and then," the 26-year-old said of the day they followed him to a Nando's restaurant.

"They can stay there for up to two hours while I 'produce', but I had to explain to them that I also needed to eat following a hard training session.

"I wanted some spicy chicken and asked if I could go to the local restaurant. They said okay as long as they could come along with me.

"They jumped into my car and off we all went. When we reached the restaurant they sat at a table next to mine.

"I don't know if they were hungry, I never asked them and I wouldn't have paid for it anyway, but I enjoyed my spicy chicken.

"They wouldn't let me out of their sight until they had a sample and were prepared to follow me to the loo to make sure any sample was mine."

He added: "Anyone (who is) found guilty of taking drugs to better their performance in the ring and is caught should be banned for life.

"I don't have a problem providing the testers with what they need. I have been tested twice in recent weeks ahead of my title defence against Breazeale.

"They can call at your house or gym or anywhere else from seven in the morning till 10 at night. I have to provide them with details of where I am staying, what gym I am using: in fact they must be notified of all my movements.

"I can let them know where I am with a special app on my phone that details exactly where I am at any given time.

"It can become a bit of a full-time job but if I have to do it, then I have to do it."

Joshua spoke earlier in the week of his desire to demonstrate the footwork he has been working on in training.

He remains largely unproven at the highest level, but believes Thursday's face-off with Breazeale shows he is improving with experience.

"He was so tense!" he said. "100 percent I've made that mistake before - (at the) Olympics, the Dillian Whyte fight, without even knowing it.

"I was chilled (in those instances), but the occasion, you are tense. When you're put in these situations, throughout these, I'm learning through experience how to deal with that.

"Once I get it right, I'll be able to play these opponents at their own game."