Sofia Vergara ''insisted'' her assistant should be her surrogate.

Nick Loeb, who was her fiancé at the time, has alleged the 'Modern Family' star convinced her 44-year-old assistant to carry their child but two attempts, both of which took place in 2013, were unsuccessful.

The news has come to light during a court case where Nick has filed a legal complaint against Sofia - who is now engaged to Joe Manganiello - and the ART Reproductive Center in the hope of preventing destroying the former couple's frozen embryos.

Nick alleged Sofia offered her ''44-year-old friend and employee'' approximately $20,000 in gifts and mortgage payments even though her lawyer advised against it. Nick also claimed he and a doctor objected to the idea at the time.

A source said: ''Sofia insisted on it. She said the assistant was the only person she could trust.''

After the unsuccessful attempts, Nick persuaded the 42-year-old beauty to consider a surrogate agency but the pair split up soon after.

Nick reportedly wants to keep the embryos, as he wishes to have children on his own.

The source added to the New York Post's Page Six column: ''He told Sofia he would raise the children himself, they would be very well taken care of.

''He wouldn't sue her for child support. She would have no parental responsibility. She refuses to allow him to take charge of the embryos.''

It is claimed that Sofia has no intention of destroying the embryos, with a source adding: ''This is all nonsense of him trying to get attention during a big moment for her.''