On Monday, a local court in Barcelona approved a multibillion-euro restructuring plan presented by Celsa's creditors, handing over control of the firm to a group that includes Deutsche Bank, Attestor, Anchorage, GoldenTree and SVP.

Celsa's restructuring is the first major test of Spain's new insolvency law that allows debtors to make use of pre-insolvency mechanisms early and benefit from court protection.

"With the appointment of Villaseca, the funds have opted for a recognised figure and, in agreement with the government, are fulfilling the commitment ... to place the company in the hands of top independent executives with a widely recognised career," they said in a statement.

Villaseca was CEO of Gas Natural Fenosa, now called Naturgy, between 2005 and 2018, and is currently Chairman of the Naturgy Foundation.

In a statement on Tuesday, Celsa had noted that "the restructuring plan approved in court means a strategic Spanish company will be taken over by foreign investors," adding this requires authorization from the government.

Speaking to reporters in Brussels on Wednesday, Spain's acting Economy Minister Nadia Calvino said the government would respect judicial rulings.

"We will see how to apply the instruments we have, always thinking of the general interest of our country, in the protection of jobs.., of this important industrial capacity in Spain and therefore, thinking of the defence and protection of Spain's strategic interests," Calvino said.

The ruling released on Monday, which was said to be final and cannot be appealed, recognised creditors' authority to implement what the court called "the only viable alternative in the medium term for the entire Celsa Group".

Under the restructuring plan, the creditors will own 100% of Celsa's capital by converting its 1.352 billion euros ($1.45 billion) of debt into equity and part of a jumbo loan, while the maturities of the remaining debt will be extended by five years.

The creditors had been unable to agree with former owners, the Rubiralta family on how to restructure around 3 billion euros of debt.

($1 = 0.9315 euros)

(Reporting by Chiara Elisei, Emma Pinedo Gonzales and Jesus Aguado, editing by Dhara Ranasinghe and Alexandra Hudson)