The 43-year-old joined fellow cast members, including Mary Lynn Rajskub, at the unveiling of the eighth instalment of the hit TV show, which sees him return as action hero Jack Bauer.
Also making a special appearance on the night was new dad Freddie Prinze Jr, who plays CTU agent Cole Ortiz.
The She's All That star - whose wife Sarah Michelle Gellar gave birth in September - recently revealed he was so desperate to land the role, he showed up to audition unannounced and insisted on having a couple of shots at the role.
And he even sent the casting director a box of cookies when he got the part.
Meanwhile, Kiefer's sharp approach to his attire at the premiere came in contrast the headlining-hitting fashion statement he made earlier in the week.
The small screen hero appeared on David Letterman's show wearing a dress.
Fans needn't worry – the decision to wear a frock was not of Kiefer's choosing, but rather the result of losing a bet.
Walking out to great cheers from the audience, the London-born actor revealed he had lost a sports wager with a friend at the weekend and therefore had to don the green vintage number for his TV interview.
"You should have seen me shopping for this thing today," Kiefer told his host, who had quipped the dress was "quite slimming" on the star.
"I walked into a store and say 'I'm shopping for a big gal, kind of my size, pretty broad across the chest. Do you mind if I try it on?'"
"Then she just said, 'Take it'. I got kind of nervous."
David then tried to up the stakes, offering Kiefer $1,000 dollars to go on the subway in the dress. "Riding the subway would be easier," retorted the dad-of-one.
"This I think may be the most humiliating moment of my life – and I've had a couple to choose from."
The eighth season of 24 kicks off in America on Sunday, and will air on Sky in the UK from January 24.