The ceiling is caving in on former Full House star Lori Loughlin – friends reveal she's on the verge of a breakdown from her highly publicized split from hubby Mossimo Giannulli after 27 years of marriage, RadarOnline.com can reveal.

Loughlin, 61, had hoped the couple's separation was simply a break, but was crushed when Giannulli, 62, made it clear the arrangement was permanent, said pals. Article continues below advertisement

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"Lori's doing her best to put on a brave face, but the scale of heartbreak and humiliation is on another level – Mossimo has totally checked out of the marriage," shared a source.

Still, an

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