The picture of Willow Smith, 13, with former 'Hannah Montana' star Moises Arias, 20.

Johannesburg - Will Smith and his wife Jada Pinkett have some explaining to do.

According to the Daily Mail, US Child Protection Services have placed the Hollywood couple under investigation because of a picture featuring their 13-year-old daughter Willow lying in bed with her 20-year-old friend Moises Arias.

The photo, which caused a stir on social media when it was circulated, is a black and white image depicting former Hannah Montana star Arias shirtless while a fully-clothed Willow lay in front of him.

Jada Pinkett defended her daughter, claiming there was “nothing sexual” about the picture.

“Here's the deal. There was nothing sexual about that picture of that situation. You guys are projecting your trash onto it … and your acting like covert paedophiles and that's not cool,” she said in a video posted on gossip site TMZ.

Nevertheless, the Los Angeles Department of Children and Family Services have launched a probe.

According to RadarOnline, Will and Jada have been “extremely cooperative”.

“Social workers will also be talking separately with Willow, and they also want to talk to the young man in the picture with her as well,” a source revealed.

“This won’t just be one or two visits with the family, and it will likely be an open investigation for at least a month, out of an abundance of caution.”

In an interview with Metro last year, Will stated that he and his wife want to give their children the room to express themselves.

“The way that we deal with our kids is, they are responsible for their lives. Our concept is, as young as possible, give them as much control over their lives as possible and the concept of punishment, our experience has been – it has a little too much of a negative quality,” said Will.

“You can do anything you want as long as you can explain to me why that was the right thing to do for your life.” - Bang Showbiz