J.J. Abrams has, according to the Fox site, tapped new BFF Leonard Nimoy to play a pivotal role in the season finale of Fringe. Nimoy will play mysterious "person of interest" William Bell, former lab partner of Walter Bishop's and founder of MassiveDynamic. The working theory is that, because Bell worked with Walter, and is likely far more coherent than Walter, Bell has a deeper understanding of all the fringe science "mishaps."
Nimoy and Fringe creator Abrams first worked together on the new Star Trek film, which Abrams directed. The original Spock will reprise this role in the film – sort of. He will be playing "Old Spock." Just don't call him Old Nimoy.
Way to cross-promote, J.J., you old master showman, you!