On the 19th of september 2020 Theo wil be performing two concerts in BIMHUIS, Amsterdam, the Netherlands, in honor of is 90th birthday. This evening is called "Theo Loevendie and the swinging strings". Performers of that evening are Maarten van der Grinten guitar, Tijs Klaassen bass, Steve Altenberg drums, Emma Breedveld violin, Oene van Geel viola, Wolter Wierbos trombone. 
https://www.bimhuis.nl/agenda/early-show-theo-loevendie-swinging-strings/