Bjorn Gulden, who has led Puma since 2013, will move to the sportswear maker's bigger rival, Adidas, as chief executive from Jan. 1, Adidas said Tuesday, replacing current CEO Kasper Rorsted, who is set to step down earlier than planned amid mounting problems at the company.

"During his time as CEO of Puma, he revitalized the brand and led the company to record results," said Adidas supervisory board chairman Thomas Rabe. "The Supervisory Board is firmly convinced that Bjorn Gulden will lead Adidas into a new era of strength."

Adidas has been looking for a successor to Rorsted, who had initially planned to leave his post in 2023, since August. With Gulden's appointment, Rorsted is now set to step down and leave the company this week, while chief financial officer Harm Ohlmeyer will lead the company in the interim until Dec. 31.

Gulden had to leave his CEO position at Puma with immediate effect with the decision to move to Adidas; Arne Freundt was named the head of Puma with immediate effect on Tuesday.

There is apparently no clause in Gulden's contract that would have prevented a direct move to the competition after it expired.

Freundt, who has worked for Puma for over 10 years and was promoted to chief commercial officer last year, had been announced as Gulden's successor last week, albeit with a planned start date of Jan. 1.

Problems have been mounting at Adidas, which cut its full-year forecast last month. There had been indications in the spring that business in China would not pick up again for the time being, with a boycott against Western fashion brands having a long-lasting effect, and the company also faces one-off effects from its exit from Russia due to the war in Ukraine.

Adidas also ended its partnership with the artist formerly known as Kanye West last month, which it said would have a "short-term negative impact" of up to 250 million euros on net income this year.