The Glee star joined host Nick Lachey on the show and performed her tune 'Canonball', while looking beyond stunning in a black floor-length gown.
Lea's impressive frock featured a halterneck design and a cinched-in waist, plus a long skirt with mesh panels which revealed a glimpse of her sunkissed limbs.
We're not surprised she's keen to show off her figure, as Lea's been on a fitness kick recently and has been spotted hiking around LA.
Luckily she did wear a black underskirt to cover her modesty - phew!
The gorgeous starlet matched her mani to her outfit with long black stiletto talons, accessorising with several gold rings.
And while we're used to seeing Lea with straight and smooth locks, this time she opted for beachy waves which draped past her shoulders.
She upped the drama on the beauty front too, decorating her peepers with smoky grey eyeshadow paired with bold brows and pink lips.
Lea's been a busy bee recently, promoting her new single 'Louder' and her book, Brunette Ambition, which is due for release in May.
However Lea did manage to fit in a sunny getaway, enjoying some quality time with friends last month.
What do you think of Lea's dress? Let us know by commenting below as the best comment across the site each week wins £50!
Got an iPad or iPhone? Reveal Mag is specially designed to fit!
Watch Lea's music video for 'Canonball' below: