Britney Spears blew off a little pre-courtroom steam Monday at the Alicia Keys concert.

Expected to attend a Tuesday progress review hearing in Los Angeles family court with her ex, Kevin Federline, Spears decided to have a little fun first.

The singer arrived at the Staples Center at 8:30 p.m. with mom Lynne, her assistant, and two bodyguards and parked in an underground VIP parking lot to avoid photographers. There was no sign of sister Jamie Lynn Spears, who just celebrated her baby shower with her big sis in Kentwood, La., last weekend.

Spears - who according to one onlooker looked pretty and seemed psyched to be there - missed the opening act, Ne-Yo, but got there in time to clap when Keys took the stage and to get up and bop to the tunes.

Having been waylaid by swollen vocal cords that forced the cancellation of some concert dates, Alicia Keys is back in form, ready to appear at St. Louis’s Scottrade Center Sunday night.

Earlier this month, before her throat condition flared up, the singer, 27, spoke to PEOPLE while hot on the heels of having wrapped up the European leg of her “Lexus Presents the Alicia Keys As I Am” tour - which she called “one of the biggest tours that I have ever done, and to see the reaction from the people was great.”

In terms of performance style, she says, “I make people laugh; everyone sings along, we shout things out at the same time. It’s adventure and very involved. It’s something that people will want to come back to.”

Beyond the tour, she’s been at work on a documentary. “It’s called Alicia in Africa, and it’s a beautiful journey that I took with my organization Keep a Child Alive. It’s been great to see the effects of the work we have been able to do and the people we have helped. Once you’ve seen it, then you can decide what you want to donate to the cause.”

And, personally, there is her love life, about which she says only: “I am in a very stable relationship with myself - and growing by the second.”

Beyoncé will be in good

company come Grammy night. PEOPLE has already confirmed that the pop star will duet with Tina Turner - and now the Recording Academy says that Alicia Keys will also perform on the Feb. 10 telecast.

Other new additions to the performing roster include: country crooner Brad

Paisley, best new artist nominee Feist and the casts of “The Beatles LOVE by

Cirque du Soleil” and Across The Universe, who will offer a special Beatles tribute.

Other previously announced Grammy performers include: Carrie Underwood and the Foo Fighters (joined by guest conductor John Paul Jones).