And one person who is more excited than most about the Essex couple's engagement is Mario's BFF Little Chris.
The teaser trailer for the new TOWIE series sees Chris claiming his spot as Mario's Best Man.
And he exclusively told us that things are bound to get VERY messy if he has anything to do with it.
He told omg!: "I'm gonna do something really crazy like go to Vegas. Yeah Vegas!"
And as much as Mario should be getting nervous about his last holiday as a single man, we also reckon he should be pretty worried about that Best Man's speech.
Chris added: "I can't wait to do the speech. It's going to be very, very entertaining and emotional for Mario.
"If [Lucy's] still sitting there that'd be the key of how good my speech was. I won't dish the dirt on my good friend but I'll put a few stories in there."
[Related story: TOWIE's Little Chris set for wrap party date]
[Related story: TOWIE's Mario gets tattoo dedicated to Lucy. Aww]
But the cheeky Essex chappy is a little worried he doesn't have the job in the bag just yet.
He told us: "Mario said on Loose Women his Best Man is going to be his mum. Could you imagine your mum organising your stag do? You'd end up down at Gala Bingo.
Messing up his mate aside, Chris is not as manly as you might think.
Before his trip to Marbs this summer, he joined the rest of the TOWIE bunch including Mario and Ricky Rayment in getting his teeth whitened at LoveLite in Harley Street.
And he told us he is very particular about his grooming regime. He said: "I take a lot of time over my appearance. I'm a bit of a diva when it comes to this. I won't have any hairdresser. I own six cones for different parts of my hair.
"I take about 45 minutes to get ready. It's bad when you're just going to Nandos or something."