Beyonce Kicks Off Oscars at Compton Tennis Court, Blue Ivy Cameos

This year's Oscars got off to a great start -- with Beyonce leading the charge with a musical number that wasn't even in the building ... and a little help from her kid.

Venus and Serena Williams were the first faces we saw Sunday as the telecast got underway from within the Dolby Theater in DTLA, with the two super star athletes immediately tossing things to Bey ... who did a live performance of her song 'Be Alive,' and doing so from a tennis court in Compton.

This is where Serena and Venus got their start when they first learning the sport, which they alluded to in their comments. And to mark the special occasion, the entire court was draped in lime green covers ... as was Beyonce and the rest of her dance troupe.

The catchy tune is featured in the Oscar-nominated film 'King Richard,' which tells the story of Serena and Venus' father, Richard Williams ... who was portrayed by a stellar Will Smith. Of course, 'Be Alive' itself is up for Best Original Song ... which explains Bey's appearance.

She wasn't the only one from the Carter-Knowles family that was on the court though -- young Blue Ivy herself was also on hand. Indeed, that was her dancing down in front with the sunglasses on ... seems they were trying to keep her presence low-key.

She was spotted nonetheless, and based on how well she was moving ... BI might just have a future job as a dancer. Lucky for her, mom and dad are always in need -- so she'll probably always have a slot booked.