So there was no lack of fanfare at Suri’s arrival yesterday, which triggered all the expected headlines about a 'TomKitten', dominated the evening news and prompted speculation about whether Cruise had, as he had jokingly pledged, eaten the placenta.

But back to the happy timing. Not only was Suri in sync with the MI:III publicity juggernaut, she managed to upstage the arrival of actress Brooke Shields‘ new daughter, Grier.

This matters because Cruise and Shields, who gave birth just a few miles away in Los Angeles, are arch enemies who last year engaged in a public spat over a not unrelated topic - postnatal depression.

It seemed that no sooner had Shields, 40, released a statement about Grier’s arrival via People magazine than Cruise’s spokesman Arnold Robinson was cranking out a press release: "Tom Cruise, 43, and his fiancee, Katie Holmes, 27, joyously welcomed the arrival of a baby girl, Suri, today,” he wrote.

A coincidence, no doubt. But the top entertainment story of the moment (Brooke’s baby) was immediately ousted by little Suri.

After Shields gave birth to her first baby, also a girl, in 2003, she wrote a book about postnatal depression, describing how she battled the condition and recovered with the help of Paxil, an anti-depressant.

Her revelations prompted unsolicited and fiery comments from Cruise, who attacked her use of drugs, asserting there was no such thing as a chemical imbalance, that psychiatry was a form of pseudoscience" and all psychiatric problems could be cured through "vitamins and exercise".

Shields responded with a New York Times piece, What Tom Cruise Doesn’t Know About Oestrogen, that described the actor's comments as "irresponsible and dangerous”. She said she "wouldn't take advice from someone who devotes his life to creatures from outer space" and that Cruise "should stick to saving the world from aliens and let women who are experiencing postpartum depression decide what treatment options are best for them".

Not that there’s any suggestion the battle could continue down the generations but Suri was also a few pounds heavier than Grier. Watch out, Shields Jnr.

In the meantime let’s just hope for Katie’s sake she doesn’t experience any post baby blues.

Silly rabbit. The real battle will be the forces of good versus the forces of evil for the fate of planet earth. No matter which side comes out on top, guarantee you Cruise will get $30 million to star in the movie version.