Celebs know how to rock the register when it comes to engagement rings. Try these baubles on for size:

PROMIS CUT

Hottie-hubbie Brad Pitt spent months with Italian designer Silvia Damiani creating Jennifer Aniston’s $200,000 spiral ring, which is engraved with "Brad 2000" and has 20 diamonds. Yes, we all could use a Boy Troy of our very own.

PRINCESS CUT

Sarah Michelle Gellar’s $100,000 3-carat gem proved Freddie Prinze Jr. to truly be a prince.

ASSCHER CUT

Ryan Phillippe gave Reese Witherspoon a 4.5-carat Neil Lane ring. Estimated cost: $300,000 — no cruel intentions there.

PEAR-SHAPED

Nick Lachey proposed to Jessica Simpson with a $200,000 4-carat diamond while yachting in Hawaii. Blonds really do have more fun, don’t they?

ROUND CUT

Mary J. Blige’s music producer husband, Kendu Isaacs, gave the diva a 7.5-carat number worth $750,000. Rock on.

MARQUIS CUT

Never to be outdone by anyone, Michael Douglas followed his basic instinct and proposed to Catherine Zeta-Jones with a 10-carat antique Fred Leighton ring estimated at $1 million.

EMERALD CUT

Nothing but the best for Tony Soprano’s little girl. A.J. DiScala proposed to Jamie-Lynn Sigler with a 6.5-carat diamond worth $500,000. Bada bling.

EDWARDIAN

Material Mom Madonna got her 5-carat three-round diamond gem from her guy — Guy Ritchie — when she brought baby Rocco home from the hospital. Talk about a holiday.