The song, "White Room", features an introduction in 5/4.
But supergroups didn't start in the 1960s. I just ran across an example from the 1780s! Vienna, the center of the music world at the time, was densely populated with excellent composers and performers. One of the great, long-standing traditions was that of the music salon (this is where the name of my blog came from). Musicians and music-lovers would get together on an informal basis, just to enjoy making music. On one epic occasion in 1785 at the home of Stephen Storace, an English opera composer and brother of the singer Nancy Storace, a few musicians got together to play some quartets. First violin was played by the famous composer and violinist Carl Ditters von Dittersdorf, second violin was played by Joseph Haydn about whom I have written so much, viola was played by Wolfgang Amadeus Mozart one of the most famous composers of all time and the cello by Johann Baptist Wanhal a student of Dittersdorf and prolific composer in his own right, author of one hundred string quartets.
Alas, there is no YouTube clip of that evening! So we will have to be content with listening to a quartet by Joseph Haydn. The Quartet No. 35 in D minor, op. 42 was composed in 1784 so it may well have been played that evening:
In his memoirs the Irish tenor Michael Kelly, who was present, recalls:
A greater treat, or a more remarkable one, cannot be imagined ... After the musical feast was over, we sat down to an excellent supper and became joyous and lively in the extreme.