By peoplestaff225
Updated January 19, 2009 07:00 PM

With two school-aged children, Paul Bettany has officially entered the era of the bullies and the bullied. Unfortunately, his 11-year-old step-son Kai recently found himself a member of the latter camp — despite Paul’s best efforts. “You get taught how to be bullied, essentially, in England,” the 37-year-old actor says, when asked the difference between schools in the UK and schools in America. “I was so worried about it, I tried to teach my eldest how to punch the day before he went to school.”

After Jennifer assured Paul that Kai — who is attending his mom’s alma mater — would be fine, and that in all her years there she never witnessed a single fight, Paul says his reaction was mixed. “I was filled with relief but also this sense of, ‘What are they teaching my kid at this school?'” he jokes. “If it’s not about fear and violence, what is it you are teaching?” When Kai reported back to Paul that he had, indeed, been bullied a “furious” Paul snapped into action, however!

Both Kai and his little brother Stellan, 5, are “bright kids” who are “really into astronomy,” Paul reveals — and one planet gives them the giggles like no other. “It’s a privilege being a parent; there are many beautiful moments as you’re bringing your children up….seeing them born, seeing them take their first step, their first word, their first bike ride,” Paul explains. “The most moving moment so far has been when they discovered the planet Uranus.”

Kai is Jennifer’s son from a previous relationship. Paul’s new film Inkheart is in theaters Jan. 23.