Sean Penn has joined the acting unions battle in Hollywood, urging his fellow Screen Actors Guild members not to vote for a new deal proposed by the American Federation of Television and Radio Artists (AFTRA).

The movie star's thoughts about the deal-- aimed at avoiding a summer strike-- were sent in email form to all 44,000 SAG members on Thursday, after Penn had recorded a 30-second phone message, which hit union members earlier this week.

Penn's message comes as SAG members choose whether or not accept the AFTRA deal proposal in a vote on Tuesday.

In the email, the actor/director writes, "AFTRA's deal not only falls short of fair compensation and protection for actors but just as significantly reflects corporate appeasement that will have an irreversible negative effect on the integrity of the show and the films we perform in. They're trying to buy us out, bully us down and, in so doing, they will destroy the very purpose of our work."

SAG and AFTRA bosses have made competing last-minute appeals in a bid to seek fair working conditions and royalty payments for their members as the second major Hollywood strike in a year looms.

AFTRA members are supporting the deal, which is believed to be similar to the one that ended the Writers Guild of America (WGA) strike earlier this year.

-Sean Penn Pictures

(This news article provided by World Entertainment News Network)