Björn made an appearance and gave a speech at the 10th Anniversary performance of Mamma Mia! The Party in Stockholm.  That makes it 10 years since all four members of ABBA, seemingly spontaneously, appeared together at the première and waved to the crowd.  Looking back, it seems that was the start of all kinds of magic we've experienced since 2016.

1. Magnus Carlsson
   One of the members of Alcazar, Magnus Carlsson (and well-known ABBA fan) posted brief footage of Björn's speech on his Instagram page.
    
2. Mamma Mia! The Party
3. Mamma Mia! The Party
   The official Mamma Mia! The Party Stockholm Instagram page also posted a couple of videos of Björn';s speech.
    
4. Rik Eijer
   Thanks to Dutch fan Rik for sharing his video of Björn's speech.

Thanks to Rik Eijer and Magnus Carlsson.