Let me be sure I name them correctly:
BillÂ Nighy played Rufus Scrimgeour in the Harry Potter films and has a appearance as Vincent van Gogh expert in the Doctor Who episodeÂ Vincent and the Doctor.
ShirleyÂ Henderson played Moaning Myrtle in the Harry Potter films and played Ursula Blake in the Doctor Who episodeÂ Love & Monsters. Do you remember? She had her face fused with a slab of pavement by The Doctor.
ZoÃ« WanamakerÂ played Rolanda Hooch in the Harry Potter films, and the last living human named Lady Cassandra in several episodes of Doctor Who.
David Tennant played Barty Crouch Jr. inÂ Harry Potter and the Goblet of FireÂ and the tenth Doctor.
TobyÂ Jones voiced the character of Dobby the House elf in the Harry Potter films and played the Dream Lord in the Doctor Who episodeÂ Amy’s Choice.
Michael Gambon played Albus Dumbledore in the Harry Potter films and both Kazran & Elliot Sardick in the Doctor Who episodeÂ A Christmas Carol.
Helen McCrory played Narcissa Malfoy in the Harry Potter films, and a Saturnynian queen named Rosanna Calvierri in the Doctor Who epsiodeÂ The Vampires of Venice.
Additionally, not shown in the picture found on pinterest, JohnÂ Cleese played Nearly Headless Nick in the Harry Potter films and has a small cameo in a Doctor Who episode titledÂ City of Death.