Hilary Duff is struggling to make sense of her son's homework.

Hilary Duff and son Luca (c) Instagram

Hilary Duff and son Luca (c) Instagram

The 'Lizzie McGuire' star's seven-year-old boy Luca - whom she has with ex-husband Mike Comrie - is in second grade and the actress has admitted she is "terrified" of next year because she has no clue about his current school work and suggested it's because she left "real" school in third grade to focus on acting.

Alongside a picture of her and Luca sat at the dining table, she wrote: "This guy with his spirit and kindness Homework is already no joke in 2nd grade. I stopped going to "real" school in 3rd grade so I'm actually doomed... I am left scratching my head alll the time looking at his homework and I'm terrified for next year! Although Singapore math is the s***....also learned a lot about tick birds this week. #rhinosbegrateful (sic)"

Meanwhile, Hilary - who also has 11-month-old daughter Banks Violet Bair with fiance Matthew Koma - is set to return to screen as her popular Disney Channel character Lizzie McGuire when the show reboots with a sequel series on streaming service Disney+, and she has said she's interested to see where the story will go, as the character will be living a very different life to her.

She said recently: "I have said this before, but for me coming back when she's 30 and she's not in a marriage and she's not having a baby and she's not doing all the things that I have already done in my life, that story is really exciting for me.

"I think to myself, where can we go? What are the struggles of a 30-year-old right now? What are the pressures that life throws in front of a woman who is 30 and doesn't have all the things yet? And for me, that's Lizzie McGuire, she had those struggles in middle school where she didn't have a place where she fits in and you know [...] always on the struggle bus, but she's also your best friend, and that's exactly what I want to target and hit home again - is being there for girls in this time of their life."