The Beach Boys played the Civic Arena in Pittsburgh on April 17, 1974 with Steely Dan as the opening act. Now that was a strange combination.
Steely Dan was introduced by one of their roadies as Mr. Steely Dan. See the description here of a similar introduction.. They had two drummers but no horn section. On “My Old School”, they used a guitar to cover the horn pars.
The Beach Boys had 10 people on stage but Brian Wilson wasn’t one of them. At one point, they had five people playing keyboards. The audience was not interested in their modern work, they only wanted to hear the oldies like “Fun Fun Fun”. This was sad as the Beach Boys were making some good music in the 1970s which built on their old stuff but was more sophisticated.
This is a Beach Boys show from that era,
Here’s a Steely Dan show from 1974.