Leonard Nimoy at the Los Angeles Premiere of 'Star Trek' held at Grauman's Chinese Theatre. Hollywood, California - 30.04.09

Nimoy, who returns for a cameo in the hit new movie, is still bitter about being left out of the Next Generation films and Shatner refused to play a cameo in the new J.J. Abrams blockbuster.

The two actors have remained good friends over the years - and have a gentleman's agreement never to talk Trek.

Nimoy tells the Los Angeles Times, "Bill and I have spent some time together, we have dinner periodically, and frankly, it's a subject that we avoid.

"It's not a fun subject right now. And I sympathise with him (Shatner) because I was left out of the Next Generation films. It is what it is.

"In the Next Generation movies, I did not appear and Kirk was killed. It was as though someone was trying to create a dividing line between the original, classic series and the New Generation crew. I was out and Bill was dead.

"I assumed that was it, it's over. I didn't feel great about it, but I was OK with it. I've had my run, and I had a lot of other interesting things I wanted to do. I didn't look back."

Source: WENN