Addressing the audience, Holmes's costar John Lithgow announced, "Tom Cruise, our good friend, devoted fan to the show, doting husband of Katie, could not be here tonight. He's heartsick that he couldn't be here ... but he wanted to make his presence felt. So, he's joining us, inviting all of you, to celebrate Katie's birthday."
And with that, crewmembers wheeled out a five-tiered, white-frosted, circular birthday cake as the crowd cheered and applauded.
"I planned it so that when she comes out for the standing ovation, John [would] get the whole audience to wish her a happy birthday," Cruise – who was in Los Angeles to premiere his new film, Valkyrie – told PEOPLE, just as the surprise was sprung.
"It's going to be great," he said, adding that they'd already had a private celebration the night before. ("That was the big one," he noted.)
Suri Helped, TooA genuinely surprised Holmes, who had been celebrating her birthday all week long, brought her 2-year-old daughter Suri on to the stage as the cast – including Dianne Wiest and Patrick Wilson – encouraged the entire audience to sing "Happy Birthday." Together, the mother-daughter duo blew out the candles.
Speaking softly, Holmes graciously thanked the audience, saying, "Thank you for coming out to the show tonight. It was a real pleasure."
The cast and crew then disappeared offstage, where they enjoyed dessert and champagne, courtesy of Cruise.
Meanwhile, across the country, the Top Gun was waiting anxiously to hear how his elaborate plan played out.
"I'm waiting to talk to her now," he said, "to see her reaction."
Additional reporting by SARA HAMMEL
Inside Katie's surprise 27th birthday bash!
With Suri at her side, Katie shows she's a stylish mom
Get the scoop on celebrity birthday parties!