How does a play change after opening night has come and gone and the production - the one in question here of course being War Horse -- has mushroomed into a hit? According to Carol Channing, the old-school Broadway diva who is the subject of a new documentary ("Carol Channing: Larger Than Life") playing this weekend at the Tribeca Film Festival, "When your show is a big success, suddenly the whole world shows up at your dressing-room door." 

"The whole world" may pay homage at the door of a diva. But War Horse is not conducive to such creatures. (I am thinking of having tee shirts run up for the cast, blazoning: "This Is A No-Diva Zone!") So how do these actors console themselves for the abundance of stars in the audience but the relative paucity of them thundering through the hallways backstage post-show? 

For one thing, they take comfort in visits from friends. There is a sign-up sheet on the show's giant bulletin board backstage; on it, actors write down the names of expected after-performance guests. These people troop through in the ritual that History Boys writer Alan Bennett once memorialized in an essay called "Going Round." Bennett said that such visitors must give a performance "to surpass the one you have just seen on the stage. And whatever you thought, even if you slept through the whole of the second act, you have to go in there saying it was all marvellous. Marvellous. It was MARVELLOUS." 

Since many of the friends of the War Horse actors (many of the friends of ALL actors) are other actors, I am sure that this month's backstage visitors have been giving performances consisting of nothing but Marvel-speak. 

Can the War Horse cast also console themselves, post-opening, with the knowledge that, even if celebrity visitors to the show aren't indulging in the post-show Going Round ritual, that they are at least in the house? Of course they can. Wouldn't you get a little jolt every night knowing that the person you grew up idolizing - whose every move you rehearsed and rehearsed in front of your bedroom mirror - is now watching YOU? I'm speaking here not just of Madonna and Hilary Swank and Sally Field and Sting, who are among the many big names who've seen War Horse to date, but of a certain very dapper New York Yankee who saw the play the other night. When I approached him after the performance and introduced myself, hoping to glean a blurb for this blog, he responded, "Just say I loved it. And don't identify me - officially, I'm supposed to be somewhere else tonight." (Needless to say, the athlete-in-question wasn't Jeter or A-Rod: no going incognito for them.) 

The final way that the War Horse cast has been recovering this week from opening-night hoopla has nothing to do with divas or celebrities or which friends come round afterwards. It has to do with rehearsal. On a couple of afternoons this week, some of the cast have been doing scene work (and understudy work) on the Beaumont stage. You thought that, once a show, in late-rehearsal period, is "frozen" in place that refinement outside of show-time comes to an end? Not a chance. I've said it before on this blog and I'll keep saying until the last guest has departed the show's final-performance after-party: War Horse actors are athletes. And like athletes - like baseball players, say, who take batting practice and then perform for nine innings (and then, if it's a day game, slip off to see War Horse) - this group is preparing for show-time all day long. For that commitment, hit status offers no exemptions.

Brendan Lemon is the American theater critic for the Financial Times and the editor of lemonwade.com.