"One does get asked quite regularly how one feels, and of course it does change throughout the day. I feel obliged to take my temperature or something," the actor, 50, joked Monday at the annual luncheon for Oscar nominees in Beverly Hills.
If only he could clone himself, that might help.
"One of the complicated things about this rather out-of-body experience is it's as if there are two of you, and one of you has to interview the other one to find out how one feels at any given moment," the Best Actor nominee says.
Joking aside, Firth is clearly thrilled to be recognized for his work in The King's Speech, though he says he's not allowing himself to get too carried away.
"Obviously it's elating, and I have a feeling that however this feels is going to percolate throughout the next six months or so," he says. "I'll probably punch the air in May at some point and crack open some champagne in September when it all sinks in."
The 83rd annual Academy Awards will air live Sunday, Feb. 27, at 8 p.m. ET (5 p.m. PT) on ABC from Hollywood's Kodak Theatre.
Reporting by MICHELLE WARD