The American Beauty star was in London on Wednesday to promote the new initiative called Old Vic Productions for which he will also act as consultant.
Passionate about the London stage and the Old Vic in particular, Spacey revealed that he had also invested more than £100,000 of his own money into the venture.
"It continues to be the favourite theatre I've probably ever played in," Spacey said about the famous London venue.
The American - who turned 41 on Wednesday - explained he had first been introduced to the Old Vic as a child, and had been enthralled by it since then.
But, he said, it was only when he appeared there last year in The Iceman Cometh that he became interested in getting involved in securing its future.
Ambition
Spacey's own immediate future, however, lies in films.
Considered one of Hollywood's hottest properties since his award-winning performances in American Beauty and The Usual Suspects, he is lined up to do a string of movies.
His first project is a film called K-Pax, in which he plays a mental patient who may come from another planet.
In time, however, Spacey said his dream would be to return to the London stage in a comedy - ideally co-starring veteran British actor Peter O'Toole.
"I hear he is very naughty on stage - so I might giggle a lot," said Spacey.
The play would, he added, be run by American Beauty director Sam Mendes.
If Old Vic Productions proves successful Spacey could find he is able to tie in both sides of his career in more ways.
One of his ideas for boosting theatre attendance is to introduce film shows so that places like the Old Vic don't just "rest on tradition".