United Kingdom, March 24 -- Sadie Frost is refusing to throw a big party to celebrate her upcoming 60th birthday.

The actress reaches the major milestone in June but she's decided she doesn't want to gather a crowd together for an extravagant bash because she feels "overwhelmed" in "big social situations" due to her ADHD (attention deficit hyperactivity disorder).

She told OK! magazine: "I don't like the idea of just getting everyone together for a big party. I like small little things, you know? Even the premiere for [hew new film] 'Twiggy' was overwhelming.

"I know everyone says they have ADHD, but I do - and I've had it for a long time. I find big social situations not much fun. I get overwhelmed.

"So I'd rather do something smalle...