BBC Director General Tony Hall says he is "a fan" of Jeremy Clarkson as an investigation into the Top Gear host's altercation with a producer continues.
The 54-year-old presenter was suspended yesterday amid allegations he "aimed a punch" at a producer.
Mr Hall said he was "involved" in an investigation that was "going to gather the facts" about the incident.
Speaking after addressing MPs on Parliament's European Scrutiny Committee, Hall said: "We have got an investigation going on.
"The most important thing in anything like this is to gather the facts. We do not have the facts at the moment.
"I am a fan of Jeremy Clarkson but this is a serious thing that is alleged to have taken place."
The BBC has given Jeremy Clarkson the all-clear to present Have I Got News For You, despite axing him from Top Gear over a recent "fracas".
Chris Evans has said rumours he will be taking over Top Gear are "absolutely nonsense."
Supporters of the suspended Top Gear presenter presented a petition signed by hundreds of thousands of people to the BBC today.