Cardi B's Grammys ensemble weighed a whopping 18 pounds.

The 'Up' hitmaker has revealed her custom-made rose gold chrome outfit designed by Rey Ortiz was as heavy as it looked when she performed 'WAP' alongside Megan Thee Stallion in the ensemble at the ceremony at the weekend.

She captioned a post on Instagram: “Eighteen pounds on my body. I had to wear it tho it was amazing. (sic)"

Ortiz recalled how the 'I Like It' rapper's stylist, Kollin Carter, said the outfit "needs to be fully danceable, sexy and comfortable … [and] I know you can do it because you also dress drag queens.”

The designer also shared how they were making adjustments to the piece right up until the last minute.

Ortiz added: "Even 10 hours before the performance we had the task to make this monster of a project work by continuing to do last-minute modifications without compromising the design."

Meanwhile, the 28-year-old star recently claimed it cost $1 million to shoot the music video for 'WAP'.

The bold promo - which saw she and Megan film at a mansion with real-life snakes with the likes of Kylie Jenner and Normani - cost the eye-watering sum, Cardi told a fan on Twitter.

First of all, the 'Press' rapper shared that the video for her 2017 major-label debut single, 'Bodak Yellow', cost $15,000.

She wrote: "Fun fact : Bodak yellow music video cost me 15 thousand dollars .I was in Dubai and I said ....I gotta fly picture (videographer) out here ...BOOM BOOM BANG ! Ya know the rest . (sic)"

A follower then replied: "girl that’s a lot (sic)"

However, Cardi responded with the cost of 'WAP' and 'Money' and 'Please Me', which came to $400,000 and $900,000, respectively.

She wrote back: "Naaaa honey ....Money cost 400K ,Please me Cost 900K ,Wap Cost a M ! (sic)"