Two profs - joint letter of rec possible?

[wrackani]

Hi y'all, 

I worked on an independent research project for my Masters thesis with Prof 1 and Prof 2 as my advisors. 

Now, I am applying to be a PhD student for Prof 1. I don't wanna bring him into a quandary by asking him to write me a letter of rec for, well, himself. Nevertheless, this was my most recent and most important research experience, so I want a letter of rec from this experience. 

Prof 2 was my secondary advisor that established the connection to Prof 1 in the first place. So I came up with the idea to ask Prof 2 if he'd be willing to work on a joint letter of rec with Prof 1.

What do you guys think about this idea? I know it's common for PhD student and a Prof to write a joint letter, but is it common for two Profs to write one together?

Thanks in advance!

[TakeruK]

First, it's not weird at all for a prof to write a letter of recommendation to the school he/she already works at. This happens all the time in Canada, because our MSc and PhD programs are separate (MSc is 2 years, PhD is the following 3-4 years). If you stay at the same school for the PhD, then you have to re-apply to it, including getting transcripts and LORs etc. So, this happens all the time! Remember, it's not just your prof that will read your application, the others in the department will too and you will be competing with other external and internal applicants for the PhD spots. Having a letter from the prof would be very good.

Second, what do you mean by "joint letters"? It's only a joint letter if both authors sign it. In my field, while a PhD student and a Prof might write a letter together for an undergrad/Masters student that worked primarily with the PhD student, the letter is only signed by the Prof, not both. So, it is no different than a letter that the Prof wrote by themselves.

So, my opinion is to ask for a letter from both profs, or just get the letter from your own advisor. You can also talk to the two of them about this.