RUMOR MILL: Sasha & Isla Postpone Wedding?

According to the British press, Sacha Baron Cohen and Isla Fisher have had to put their wedding plans on hold -- because she's taking too long to become Jewish!

Isla is converting so that she can share the same religion as Sasha's family and have a traditional Jewish wedding.

But the MailOnline Web site reports that it's taking her much longer than she expected to adopt the faith.

The Wedding Crashers star has been working her way through the Torah studies that she has to complete before converting.

But between filming her new movie, Confessions of a Shopaholic, and looking after their baby, Olive, the Aussie star is falling behind.

Now it looks like the couple, who have been engaged since 2004, are going have to cancel their plans for a summer wedding to give her time to catch up.

"Right now there's no wedding date set because Isla hasn't fully converted yet," said the site's source, "and even though she's working at it part-time, she's far from being close to completing her studies."

And apparently the hold-up it isn't going over well with Sasha folks!

"It's very much frustrated her future in-laws, especially Sacha's parents, who were really hoping for a wedding this summer."

Isla's rep has not yet responded to our requests for a comment.