Beyonce Gearing Up for 'Huge' Coachella Performance with 11-Hour Rehearsal Days

Beyonce's on a mission to make up for lost time -- ramping up her Coachella rehearsals to ensure her performance is one for the ages after missing out last year ... TMZ has learned.

Sources close to Queen B tell us ... she started getting serious about practicing for her show Tuesday, scheduling 11-hour days in a high-profile L.A. studio that's been booked solely for her and her dancers, choreographers, technicians and other members of her crew.

We're told there are 7 security guards patrolling the studio inside and out to keep the rehearsals top secret ... no unwanted guests or recordings.

Our sources say Bey began planning for this gig as far back as last year, of course ... when she was slated to headline the 2017 festival before she had to back out due to her pregnancy with twins.

She clearly wants to make sure everyone gets their money's worth this time around.

We broke the story ... another huge act, Cardi B, is pregnant and on the Coachella lineup this year, but she says she's not going to let it stop her from taking the stage.