Many happy returns: Ian Holm

John Walsh on the gravitas of a great actor, 84 today

As many theatrical knights have discovered, taking a key part in a blockbuster movie can be a double-edged sword: you're revered by millions of kids, but the role eclipses all the classy, grown-up stage and screen work you've sweated over for years. When Sir Ian Holm took the part of Bilbo Baggins in Peter Jackson's Lord of the Rings trilogy in 2001, and then reprised it for The Hobbit trilogy, did he wonder if all his training at Rada in the 1950s and his work at the RSC in the 1960s had been wasted?

Probably not. For Holm is too experienced and adaptable an actor to give himself Gielgudian airs. Not when his most famous non-Hobbit roles have been as a disembodied head, and an athletics coach who punches a hole in his straw boater to celebrate victory. The former role was that of Ash, the reserved crew member in Ridley Scott's Alien, who turns out to be a robot; his severed head, leaking milky blood, reveals the truth about the astronauts' fatal mission. Scott uses Holm's quiet creepiness to brilliant effect. The latter part was in Chariots of Fire, playing Harold Abrahams's coach Sam Mussabini, who guides the runner to an Olympic gold and whose years of striving are summed up in that triumphant gesture.

Short, compact, handsome and eerily self-confident, Holm is immensely versatile. His natural authority and gravitas won him an Olivier award for his King Lear at the National Theatre and saw him play Napoleon three times. But he thrives in supporting roles – as mysterious, unreadable men, capable of we're-not-quite-sure-what. When he appeared in the first performance of Pinter's The Homecoming, the playwright named him his favourite actor. "He puts on my shoe," he said, "and it fits".

The troubled quality in Holm's performances burst into real life in 1976 when he suffered an attack of stage fright before Eugene O'Neill's The Iceman Cometh and refused to leave his dressing-room. He took a 14-year break from theatre and devoted himself to films, with great success. "I have a dread of responsibility," he once said. "I like someone else to be in charge." That tightly-wound nerviness has been the secret of his success for 50 years. µ

Ian Holm as Puck in Peter Hall's film version of 'A Midsummer Night's Dream' from 1968