By Jacob Gronholt-Pedersen and Maggie Fick

COPENHAGEN/LONDON (Reuters) -Years before Novo Nordisk's obesity drug Wegovy became a U.S. blockbuster, then-CEO Lars Rebien Sorensen told a press conference in Copenhagen: "You ain't seen nothing yet."

More than a decade later, the 70-year-old is returning to Denmark's biggest company and is expected to strongly influence its future direction - most immediately through the selection of a new chief executive.

His appointment as an observer on the board follows the removal on Friday of current CEO Lars Fruergaard Jorgensen by Novo and the Novo Nordisk Foundation - the company's controlling shareholder, which Sorensen chairs.

Jorgensen succeeded Sorensen as CEO in 2017.

Six people interviewed by Reuters said they think Sorensen will use his influence to push for an external hire, the first in Novo's 103-year history. The company has had only five chief executives, all Danes.

A source close to Novo who spoke on condition of anonymity said Sorensen would look for someone who could recharge the company's U.S. performance, and that such a candidate was likely to come from outside.

Under Jorgensen's leadership, Novo became a world leader in the lucrative weight-loss drug market, launching Wegovy in 2021. But in the United States, its largest and most profitable market, the drug has been struggling against U.S. rival Eli Lilly's Zepbound.

The decision to remove Jorgensen showed the Foundation's frustration with management over the execution of a strategy to shift Novo's focus to obesity from diabetes care, devised when Sorensen was CEO, the same person said.

Novo Nordisk chair Helge Lund on Friday said the company's strategy is unchanged despite the shake-up.

Lund said last week the search would include internal and external candidates and Jorgensen will stay on until a successor is appointed.

The Foundation declined to comment on Thursday.

A Novo Nordisk spokesperson said Sorensen will participate in board meetings but holds no voting rights as an observer. He will become a full board member at the next AGM.

NEW STYLE

Novo's shares have more than halved from their peak when the company was valued at $615 billion in June last year, one reason cited by the Foundation for intervening to remove Jorgensen.

At one point Europe's most valuable company, its expansion bolstered Denmark's economy and the country's global standing.

Nevertheless, Friday's move stunned investors, analysts and many Danes, who viewed it as a public humiliation of Jorgensen and the company's board.