Should I lead an applause after introducing colloquium speaker? I am introducing my first speaker at my university and, since the speaker is rather famous, I wrote a 1-2 minute introduction.  The crowd will be interdisciplinary and between 100-400 people.

Should I lead the audience in an applause at the end of my introduction, or just finish with the title of his talk and a nod to him?  Or something else?

If it matters, it is an interdisciplinary topic, a public audience and in a science department.
"Please welcome our guest ..." and applaud with the crowd.

Presumably you have attended to invited speeches before?