heidispencebigD.jpgWe just caught Heidi Montag at the Santa Monica Courthouse, entering with papers in hand and three bodyguards beside her. A source close to Montag tells us she IS filing for divorce saying, "I knew it was coming. She's over it."

In fact, the reality show star went to the Malibu Courthouse earlier this morning to try to file but was told they don't handle family cases there and was sent to Santa Monica.

Our photographer snapped Heidi just minutes ago on the courthouse steps looking sad and upset but determined. She was without her trademark makeup and fancy hair but was dressed down and looking serious.

Our source tells us it may not be a full-on divorce, but they're getting close: "It's a legal separation. It's all Heidi can do until a lawyer gets 100% involved."

A spokesperson for the Santa Monica Courthouse was unaware of Heidi's visit this morning.

Looks like divorce is on the horizon -- IF this is, in fact, for real!

More information coming soon and pix too! ...