Alan Titchmarsh swops Charlie Dimmock for a diving suit in his new BBC series the Nature of Britain.
He goes underwater with award winning cameraman Dean Burman, who has filmed the private life of pike in a Leicestershire quarry.
Trailers for the programme say it feature's the pike's courtship behaviour for the first time.
It's being screened on BBC1 at 9pm on Wednesday. More here.