Chiswick Flyover in west London was apparently opened in September 1959 by Hollywood actress Jayne Mansfield (picture below). No, I don’t know why either, but you can find more details at www.stmgrts.org.uk/archives/2009/09/jayne_mansfield_and_the_chiswick_flyover.html

Perhaps more worryingly the nearby Hammersmith flyover (currently the subject of on-going strengthening work after the discovery of concrete rot) has its own, much darker, celebrity connection. Underworld legend has it that the body of Ginger Marks, slain by the Kray gang, is buried in the foundations.
Gleaned from The Londonist at http://londonist.com/2014/07/five-more-odd-facts-about-london.php