The Jessie's Girl hitmaker, real name Richard Springthorpe, reveals his son Josh kept their family bond a secret as he worked on the new rock drama, so the veteran star raised eyebrows when he repeatedly greeted his boy with a warm embrace during early rehearsals with co-stars Meryl Streep and Kevin Kline.

He explains, "I'm a very hands-on dad and Josh didn't tell anyone that I was his dad. So when we were doing the two week rehearsal before... I'd come in every morning and I kiss him and hug him and then go to work, and then after a couple of mornings, one security guy came up to him and said, 'Dude, what are you doing with Rick Springfield? Leave the actors alone. Don't do that.'

"He thought there was something weird going on, and even then, Josh didn't say, 'Oh, he's my dad!'; he just said, 'Oh, OK!'".