Reese Witherspoon's 4-year-old son, Tennessee James, is learning how to spell, but it seems the one word that's giving him the toughest time might be his own name.

The Big Little Lies star took to Instagram on Tuesday to show off her little boy's attempts at writing his name -- and admitted that the task can be a bit difficult.

WATCH: Reese Witherspoon's Sons Were Twinning for the Super Bowl — See the Adorable Pic!

"When your name is TENNESSEE, it's a bit tricky to learn how to spell it," Witherspoon captioned the cute pic, which she tagged "#PreSchoolProblems"

Witherspoon and her husband, Jim Toth, welcomed Tennessee in September 2012. The actress is also the mother of a 17-year-old daughter, Ava Elizabeth, and 13-year-old son, Deacon Reese, from her relationship with ex-husband Ryan Phillippe.

NEWS: Reese Witherspoon Shares Cute Photo of Son Tennessee on Set: 'Introducing My New Makeup Man'

Recently, Witherspoon spoke with ET, where she opened up on her parenting philosophy, and the questions that all parents face.

"We're all just trying to be the best parents we possibly can be," she said, "so I think it's always that question: Am I doing the right things? Am I exposing them to the right things? Am I disciplining the right way?" Check out the video below to hear more.