This is one of those topics that I can't believe no one else has written about, and to be upfront with you, I won't do it justice here. This post will be short and sweet (like Andy Milonakis dipped in honey), focusing primarily on their music - and in the process, providing you with a kick-ass soundtrack for your working day.
1. Dedicated EPIC songs to their mothers.
Both were abandoned by their fathers extremely early on, in Lennon's case his mother also abandoned him, but they were reunited briefly (long enough for her to introduce him to music) before she was killed by an off duty police who was driving drunk.
2. Dis tracks targeted at their ex-best friends
One of Tupac's most notorious tracks is his dis track against Notorious (see what I did there?), but did you know that decades earlier, Lennon released a dis track against Paul McCartney? Boom!
NOTE: if you are unfamiliar with Tupac's lyrical style and are in an easily offended environment, I recommend wearing headphones
3. Metaphor of a gun as a woman and a woman as a gun
This one may be a stretch since no one knows exactly what the Beatles' Happiness is a Warm Gun is about exactly (John Lennon insists it is not heroin), a popular theory is that the gun is a metaphor for a woman (I'll let you connect the dots there). Whilst Tupac's Me and My Girlfriend is more obviously a metaphor for a gun ("Picked you up when you was nine, started out my life of crime with you, bought you some shells when you turned twenty-two...")
4. Makaveli & Plastic Ono Band
A lot of people seem to forget that the album The Don Killuminati: The 7 Day Theory was not a 2pac album, it was the first (in a potentially longer series) of albums to be released under the alias "Makaveli" (these days most people wrongly refer to that as the album name).
John Lennon felt a similar need to re-invent himself on his first album away from the Beatles; John Lennon/Plastic Ono Band. Both albums represent a departure from their usual style with a much darker / angry tone and an emphasis on an almost violent raw emotion and almost ZERO radio friendly tracks.
NOTE: I cant include the entire albums below so do youself a favour and look that shiz up! but you can listen to the below for starters.
My laziness prevents me from proving it, but the parallels don't end there, trust me there are more than four! This half-assed post really does only scratch the surface, but if I have managed to convert a couple of Tupac fans into Lennon fans, and some Lennon fans into Tupac fans, I will be happy.
UPDATED: I have found a few mash-ups of Tupac and Lennon on YouTube, this one is by far the best: