Macaulay Culkin has "no secrets" with Brenda Song

He told E! News: "Brenda and I are very good at communicating with each other. We have no secrets. We're constantly on the line-we talk, we talk."

The 'Home Alone' star has devised a system called "tagging out" with his significant other, where he and Brenda both acknowledged when they need to have their own space for a period of time.

He said: "I call it tagging in and out. You know, 'You tag in.' Like wrestling. 'Hey, I've been at us for about three hours. I need to tag out. I need quiet time.' We call it quiet time. 'I need to go upstairs and have quiet time.

"We just talk. That's the best way to do it. We're in the thick of it, a two year old and a three year old."

The 'My Girl' actor - who was the highest-paid child star of all time at the height of his career in the early 1990s - also noted that the 'Suite Life of Zack and Cody' star is the "best mom" and that he knows how "lucky" he is to have her in his life.

He said: "God bless Brenda. She is a champion. "And she is the best mom. She's the best boy mom. She's just the best mom. She's the best person. I wake up every day knowing I'm lucky. Not feeling I feel lucky, but I know I'm lucky.