Q. What should you do if you see your ex-husband rolling around in pain on the ground?A. Shoot him again.
I'VE generally declared that it will be a cold day in hell before I speak to most of my exes again, which is why I found the sight of newly-single Liz Hurley frolicking in the Alps last week with Hugh Grant so strange, as they broke up in 2000.
After splitting from fiance Shane Warne, Liz was spotted skiing in St Moritz with Grant, who is godfather to her son, Damian. But while it may have looked like the pair were taking the piste, this strange situation reflects the bizarre trend we've seen lately of celebrities gallivanting off around the world with their exes.
Hugh and Liz's frisky little gambol in the snow is only slightly less bizarre than the fact that tantrum-throwing supermodel Naomi Campbell is jaunting around Kenya with her ex-boyfriend Flavio Briatore and his wife Elisabetta Gregoraci.
We all know holiday companions can be trying enough at the best of times, so imagine how awkward it would be seeing your one-time man parading around in Speedos alongside his newer model?
Patricia Farrell, author of How To Be Your Own Therapist, says it's possible to remain friends with an ex if the relationship was mostly platonic and you still enjoy each other's company.
In other words, if your relationship was mainly spent between the sheets, you're probably not going to be able to move your future meetings on to discussing the latest book you've read.
I don't get it. Of all the people available to hang out with in the world, why would you choose someone you once presumably dreamt of spending your life with (before it all went awry)?
I have pals who stayed friends with an ex because they made them laugh, they had been through a lot together and they still retained a fondness for them. Now I have a fondness for the strawberry yogurt I found lurking at the back of my fridge, but I know that I have to bin it, because when something has passed its shelf-life it's just not good for you.
The undisputed president of the staying-friends-with-an-ex club has to be Simon Cowell, whose behaviour towards former lovers is perplexing.
After he broke up with make-up artist Mezhgan Hussainy, he moved the Afghan-born brunette into an LA mansion that his friends have nicknamed the "girlfriends' graveyard".
"I don't pay them off, but if you have been with someone long enough there's a responsibility," Cowell said. "You can't say one minute you can live this type of life and then the light goes off."
Cowell's ongoing relationship with former girlfriend Sinitta means she regularly joins him on holiday in Barbados, and was hired as a mentor for the X Factor.
Cowell set up a trust fund for her children (his godchildren), and it was Sinitta, along with her partner Jason and two children, who spent this Christmas with the music mogul. His pregnant girlfriend, Lauren Silverman, spent it in the US with her young son.
Whether Lauren will continue being happy with this arrangement after Cowell's son and heir is born remains to be seen. It's amazing how fast an ex-girlfriend can disappear from the scene once a new partner has her feet under the table.
Naomi Campbell, please take note.