Sources say there was no prenup.

Megan Fox may have to pay up in her divorce from Brian Austin Green.

The 29-year-old "Transformers" star -- who filed for divorce late last week -- will "almost certainly" pay Green, 42, spousal support, TMZ reported Monday. The site claims Green has been suffering from vertigo and largely out of work since the couple was involved in a head-on collision with a drunk driver late last year. (Sources say the pair, who have two sons together, did not sign a prenup when they married in 2010.)

On HuffPost Live Monday, entertainment legal analyst John Burns said the health condition could have some bearing on the couple's divorce settlement:

"It's going to be huge. First of all, spousal support is intended to allow both people to maintain the same lifestyle they had during the course of the marriage, post-marriage and here you have Megan Fox, who made tons more money than the gentleman here, Brian Austin Green, so he was going to get spousal support no matter what. But the vertigo claim adds another element because he can't work, he can't do anything else ... he needs to maintain that same lifestyle and he can't do it because he can't work. That's going to increase the amount of money that Megan Fox has to pay out."

Watch the clip above for more on Fox and Green's divorce and to hear Burns' thoughts on why the couple may have skipped a prenup.

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