Christian Horner, the Formula One boss married to Spice Girl Geri Halliwell, is under investigation by Red Bull following an accusation of "inappropriate behaviour".
Horner, 50, who has been Red Bull team principal since 2005, will remain in his role during the investigation. "I completely deny these claims," he said.
A spokesperson for Red Bull — the Austrian energy drinks company which owns the F1 team — said: "After being made aware of certain recent allegations, the company launched an independent investigation.
"This process, which is already underway, is being carried out by an external specialist barrister.
"The company takes these matters extremely seriously and the investigation will be completed as soon as practically possible. It would not be appropriate to comment further at this time."
The Guardian reported there was an internal power struggle at Red Bull following the allegation, and that if proven, Horner's position would be untenable.
Horner's wife, Geri Halliwell, has not publicly commented since the news broke, but The Sun quoted a source that she was standing by her husband and did not believe the allegation.
"Geri has been in floods of tears all weekend while looking after her kids," the source said. "She is insisting Christian has done nothing wrong."