Esta TerBlanche — a star on the iconic soap “All My Children” — has died at 51, her family tells TMZ.

Barbie Ashley, her goddaughter, tells TMZ … Esta died unexpectedly on Thursday in her North Hollywood home … medical personnel believe the South African actress had been dead for about a day before she was found.

The cause of her death is under investigation, her rep, Lisa Rodrigo tells us … adding there is no other information at this time.

Esta was crowned Miss Teen South Africa in 1991 … and from there landed a number of acting roles … including her most well-known … Gillian Andrassy, a trouble-making princess, who was killed off in 2001.

She is survived by her ex-husband and goddaughter.