Strange but true
Strange but true (or strange, but true) is a phrase often used to refer to a tabloid newspaper column (such as the Weekly World News) that features unusual ("strange") stories. The c. 1937 True magazine had a "Strange But True" section on the back cover.
Perhaps the earliest use of "strange but true" in a published work is in Shakespeare's Macbeth (~1599), act III, scene IV (Ross and Old Man outside of Macbeth's castle): Ross: "And—strange but true!—Duncan's horses, beautiful and swift, the best of their kind, broke down their stalls and ran wild They refused to obey, as if they were at war with mankind."
The 1859 Notes and Queries by Martim de Albuquerque in a reprinted 1704 account by Edward F. Rimbault ("printed for R. Smith near Spittle-Fields Market") titled A most Strange but True Account of a very Large Sea-Monster.
It is strange, but true as strange, that imitation generally interests us more than reality. —Richard Grant White, Life and Genius of Shakespeare, 1865