"He is a martial arts wizard in real life - he can do standing double back somersaults, and he used to do exhibitions at the karate world championships - but I had to beat him up, and I couldn't beat my wife in a fight," said Jason.
"It was interesting to see another young person who is universally known but very different to Daniel, Rupert and Emma. The Twilight phenomenon is different," he said.
Jason added: "I am now - and have to be - Team Jacob, because Taylor is a lovely boy."
"He's been doing karate since he was six. I've done ten kickboxing lessons. We'll see how that turns out! Hollywood decided he is the latest action hero apparently, and I am there in this film to make him look even more muscular. And I will do that," he told BBC Radio 2.
The 47-year-old previously admitted to being apprehensive about the fight scenes.