Star brightening, then dimming over the course of about a minute

[Af82l8]

I'm an amiture astronomer who lives in New Zealand (southern hemisphere). 

Between about 10pm and 1:30am nzdt, on the evening of the 5th of January 2021, I was Star gazing with a friend who had never done it before. I was setting up my telescope to look at the seven sisters when my mate tells me with much excitement that he can see a star brightening dramatically. I look up and couldn't see what he was talking about so go back to setting up the telescope again. As I finish setting it up about a minute later to look up and see a particularly bright star(brighter than Sirius) start to dramatically dim back to what I can only guess was it's original brightness. Both or us saw it, so it wasn't me or him imaging things. The seat was located somewhere between the seven sisters and Orion, but stupidly I didn't think to remember exactly what star it was. And only thought to ask about it today.

Any ideas what could cause this or how I could find a record of the exact star and the event that happened. Thanks

[OceanBreeze]

Since you were observing near to Orion, the star you saw may have been Betelgeuse, but the fade you mention is much faster than anything that has ever been observed by others so doubtful.

[Af82l8]

It Wasn't Betelgeuse. I do know the main stars of Orion. There is a possibility that it was Bellatrix, but like I said from memory it was between Orion and the seven sisters. About 2/3 to 3/4 of the way towards Orion from memory, but I didn't think at the time to take note of the exact star. If I hadn't seen it for myself and had a friend who observed it also, I wouldn't be making attempts to figure out what anomily had taken place.  

If any person is aware of any 24 hour sky observations records that would help me track down what we observed, it would be appreciated.

Thanks