01/20/2012 at 01:00 PM EST
Connor Cruise, the son of Tom Cruise
and Nicole Kidman
, celebrated his 17th birthday with a charity bash
at the Staples Center in Los Angeles this week – but it was his sister, Isabella, who made news.
Bella, 19, introduced her date Eddie Frencher, who is in his early 20s, as her "boyfriend" at the party, where aspiring deejay Connor spun records in the Hyde Lounge and played Just Dance 3
with friends and his big sis.
"They were together the whole night," a guest at the party tells PEOPLE of Bella and Eddie. "They were sitting together watching the game and sang 'Happy Birthday' to Connor standing side by side."
For his birthday, Connor could choose between two years' use of a Dodge Challenger or a Jeep Wrangler. He opted for the Dodge. The Jeep will go to charity, reports the New York Post
. The event benefitted Children’s Miracle Network Hospitals
Tom Cruise, Kidman and Katie Holmes
were not present at the party.