Amanda Seyfried's son isn't actually called Thomas.

The 39-year-old actress is married to 'The Newsroom' actor Thomas Sadoski, 48, and while her fans around the world have assumed that he shares a first name with his father, she has now revealed that that isn't true.

She told US TV show 'Extra': "Everybody thinks that my son's name is Thomas… Somebody somewhere made up that his name was Thomas and I'm all for it but his name isn't Thomas. Isn't that funny?... I love that he has a secret name!"

The 'Mamma Mia!' star - who also has a seven-year-old daughter known as Nina - is now appearing in the mystery series 'Long Bright River' and plays the mother of a boy coincidentally called Thomas and she could identity with the "guilt" her character feels.

She said: "I will say like I could really relate… Mickey is a little uncomfortable as a mom and you can feel that and you can feel her guilt and I know so well what that guilt is like when you're not around but you're kind of around and you're kind of trying to instill all this information and this support all at once."

Towards the end of last year, the 'Les Miserables' actress admitted that most of her "free time" is spent when the children are at school.

Asked when she gets some alone time, Amanda told PEOPLE: "When [the kids] are at school actually. I always kind of get something out of all the time that I have."

The Hollywood star is always firmly focused on her children when they're at home, but she makes a conscious effort to make the most of her free time when the kids are at school.

She shared: "In the morning, when they wake up, I'll sit and crochet while they eat their breakfast, watch 'Bluey', whatever they end up doing before school. But when they're at school, yes, I have time!"