New particulars have emerged within the dying of actress Michelle Trachtenberg … her mom tragically found her daughter’s physique in mattress Wednesday morning, simply months after her liver transplant, TMZ has realized.

Regulation enforcement sources inform TMZ … Lana entered Michelle’s Manhattan condo, solely to search out her unresponsive, mendacity on her again in mattress — Lana then referred to as police and paramedics, who pronounced Michelle lifeless on the scene.

We’re advised Lana final noticed Michelle alive at 10 PM Tuesday, and he or she was clearly energetic regardless of her well being issues — the “Gossip Woman” actress was even out with buddies final Thursday evening at Sartiano’s in NYC.

Our sources additionally confirmed that Michelle not too long ago had a liver transplant, inflicting issues together with her liver and thyroid. Earlier immediately, TMZ reported Michelle’s physique could have rejected the transplant, presumably resulting in her dying.

Regardless of her well being points, Michelle defended her gaunt and frail look on-line in latest months, insisting she was “glad and wholesome.”

Michelle’s household has requested for privateness throughout this devastating time and did not launch additional particulars of her stunning dying at 39.