'White Lotus' star Jason Isaacs reflected on managing money 'immaturely.' A financial planner breaks down how to avoid doing the same.

Jason Isaacs in "The White Lotus."

HBO

• Jason Isaacs said he's spent "pretty much everything" he's earned as a TV and movie star.
• Isaacs said he "immaturely" matched his spending and income, so he hasn't saved as expected.
• A financial planner told Business Insider how to avoid lifestyle creep.

For a movie star, Jason Isaacs says his financial situation isn't what you'd expect.

"People will think I have huge stockpiles of money," the "White Lotus" star...