The Don't Start Now singer will take to the stage at the ceremony which is slated to take place at The O2 Arena on May 11.
She said of the news: "I am so excited to be returning to perform for you all at The BRITs this year. It's going to be truly special to be back on stage in the UK."
The 25-year-old also announced it on her Twitter account, writing: "HONEY I’M HOME AND I’M PERFORMING AT THE @BRITs DON’T MISS THIS!!!!!! #BRITS."
Lipa won the British Breakthrough Act and the British Female Solo Artist prize in 2018, as well as British Single of the Year with One Kiss in 2019 alongside Calvin Harris.
Also set to perform is singer Griff, who is the winner of this year's Brits Rising Star award.
She said: "In my head I'm still screaming from the phone call when I found out. It's honestly such a miracle: how on earth did we manage to win a BRIT and break through during a pandemic?"
Jack Whitehall is due to host the ceremony for the fourth year running.
It was originally set to take place in February but was postponed due to the coronavirus pandemic.
Chief executive Geoff Taylor said when the news was announced back in June: "We want to make sure that the Brits delivers the outstanding production levels, superstar performances and live excitement that make it the biggest night in music."
The Brit Awards 2021 nominations are set to be announced at 4pm today (Wednesday 31 March) on the Brits online platforms.
Watch: Dua Lipa to take part in Elton John's Oscar party