Rooney was dismissed at the weekend for Manchester United, which Capello made a light-hearted reference to during training ahead of England's matches against Slovakia and Ukraine.
And Beckham will now give Rooney advice if the United youngster wants it.
"Obviously, if Wayne wanted to talk to me about that, he would," he said. "We're good enough friends and team-mates. But he has Sir Alex Ferguson, a man who he'll be talking to and will respect, to speak about these things.
"And Fabio Capello, who is one of the most successful managers in football."
Beckham has pointed to the example of Zinedine Zidane to explain why there should be no attempts to rein in Rooney.
Beckham has been criticised for his temperament himself throughout his career and admits he is still guilty of ill discipline at times - but he insists calming Rooney would create a "different animal".
The 33-year-old played with Zidane at Real Madrid and believes that taking away his passion would have affected his game, with no better example than when the France legend carried his country to the last World Cup final and was then sent off for his infamous headbutt.
Beckham could see when Zidane was going to explode, and it is the same with Manchester United forward Rooney.
"When you are a bit older, you see players' reactions and see what can happen next," Beckham said. "I've seen it with some of the best players in the world. Look at ZZ, you can see it in his eyes sometimes in games. You know what's going to happen.
"It's all about the passion, which is the biggest thing. You don't want to take that out of him. You can try to get to him in time as a team-mate, but some things are uncontrollable.
"You can have some of the most experienced players in the game telling you to calm down, but sometimes you can't be controlled."
Luckily for Beckham, no manager told him to stop being passionate about winning.
"There's not been a single manager who's done that, and I've been lucky to have played under some of the best managers in football, and obviously the best manager in football," Beckham said. "He spoke with me when certain situations happened.
"I probably still haven't been able to control it fully. When things go badly, the team's losing and it's not going well, that frustration comes out.
"It's not right. It's bad. I was frustrated in the Spain game and got a yellow card for talking back to the ref. You try to control it, but sometimes you can't."