Originally Posted by Jo of Palatine
Princess Filippa's sister-in-law is the famous German actress Sunnyi Melles, now Sunnyi Sayn-Wittgenstein-Sayn of course. She still uses the Melles-name for her work in the theatre and on TV. Princess Sunnyi read the diaries of princess Filippa for the audio book production. Well worth listening to if you understand German.
Sunnyi Melles is the wife of Prince Peter Heinrich Stanislaus zu Sayn-Wittgenstein-Sayn (the youngest brother of Alexander Konrad zu Sayn-Wittgenstein-Sayn), what makes her Filippa's aunt-in-law.
The youngest brother of Filippa is also named Peter zu Sayn-Wittgenstein-Sayn, but he's just 14 years old