Sue is leaving the Field Museum’s main hall today

CHICAGO — Sue the T.rex is leaving its prominent spot in the Field Museum to make room for a cast of the biggest dinosaur ever discovered.

Museum officials say Sue, which has been at the museum since 2000, will be moved on Monday as part of an  overhaul to the main hall. The specimen will be updated and moved upstairs to a private suite opening in 2019.

Crews are set to start dismantling Sue Monday, to move her to her new spot.

Field Museum paleontologist Bill Simpson told WGN moving Sue will take more than a few days.

"I think it will take three, three and-a-half, maybe four weeks.  We've left a little bit of extra time, just in case," said Simpson.

A 122-foot-long titanosaur, a Patagotitan mayorum from Argentina, is expected to arrive in June to replace Sue.

"It's like comparing a lion to an elephant," Simpson explained, "Carnivores tend to be smaller than the plant eaters."

The new dinosaur will take up a third of the main hall with its head peeking over a 28-foot, second-floor balcony.

While many fans are posting bittersweet memories of seeing the T.rex for the first time on social media, the dinosaur's Twitter persona is keeping things positive.

"Don't be sad. Think about 2019 and the rad as heck "SUEcave" I'm getting," the account tweeted on Sunday.