Yes, he is.
When Tom and Nicole split, she made an off the cuff remark about finally being able to wear high heels again. It's also a pretty prevalent rumor that he wears shoes with platforms in them for most of his films, and that camera angles are shot in a manner to make him look taller (think John Rhys-Davies in the LOTR trilogy, except taller and not shorter).
Hmmm... I wonder if his insecurity about his height is also related to Scientology somehow? 😛
[Edit]: Is it me, or does Katie look *really strung out* in that photo? I wonder if this is also related to Scientology somehow? 😛