Lindsay Lohan is NOT Engaged!

TMZ just spoke with Lindsay Lohan's rep -- who just got off the phone with her client -- and no, she is not planning a wedding.

Reports are circulating that the rehabbing actress is betrothed to Riley Giles, whom she met at the Cirque Lodge in Utah, and that he gave her a ring. Not so, says Lindsay through her rep. The "new" ring is a gift from her father, Michael Lohan, and the other is a Cartier ring that she has had for some time.

Don't believe everything you read ... unless it's on TMZ!