Jacobs, as a fan of opera, decided to take Hergé with him to a concert. Hergé did not like opera, however, and for decades he would gently joke with his friend Jacobs through opera singer Bianca Castafiore, a supporting character in "The Adventures of Tintin". Hergé also gave him tiny cameo roles in "Tintin" adventures, sometimes under the name Jacobini.