Avengers: Endgame: 10 Instagram posts which prove that birthday boy Robert Downey Jr is the biggest MCU fan

Robert Downey Jr. is an actor you can't help but fall in love with and admire. From his Ally McBeal days to Sherlock Holmes and more, RDJ has managed to win millions of hearts. But the role that really cinched the deal for the actor and made him a bonafide superstar, it's his stint in MCU (Marvel Cinematic Universe) as Iron Man aka Tony Stark. Many would simultaneously agree that no one except RDJ was meant to play the role of the genius playboy billionaire philanthropist. 

The journey for Robert in MCU started in 2008 with Iron Man, which catapulted his career and was almost like a second birth for him. Three stand-alone films, the Avengers franchise and brief appearances in several others, Tony Stark became the Godfather of MCU. Hence, the fan theory of how Tony might not make it out alive at the end of Avengers: Endgame, it feels like the end of an era. But, one thing is for sure, there will never be a bigger fan of MCU like Robert Downey Jr.

ALSO READ: Happy Birthday Robert Downey Jr: Here are some remarkable roles of the actor that Iron Man fans might not know

As Robert celebrates his 54th birthday today, here's proof of RDJ fangirling over MCU:

His first Instagram post had to be Avengers-themed.

Come get me, Instagram... #chrisevans #chrishemsworth #jeremyrenner #scarlettjohansson #markruffalo #OG #avengers #hair @davynewkirk #style @jeanneyangstyle ( @jimmy_rich )

RDJ is Tony Stark, Tony Stark is RDJ.

I'm up for the challenge, are you? Happy New Year, everyone! #teamStark #happy #newyear #2019

He owes it all to Stan Lee.

I owe it all to you,,, Rest In Peace Stan... #MCU #Excelsior #legend #rip #stanlee #TeamStark

He fangirls over his co-stars.

Humbled by the class act that IS @markruffalo. #sciencebros #ageofultron credit @jimmy_rich

He fangirls over his own OTP's.

Happy Valentine’s Day to all the shippers out there!

RDG caught with the Stony-bug.

You know it's love with you get matching tattoos.

And last but certainly not least to the #firstavenger my brother #ChrisEvans “Now we are one...” @renner4real @chrishemsworth #scarlettjohansson #chrisevans @jimmy_rich and tattoos @joshualord

Even festivals have to be MCU-themed.

The battle begins! Merry Christmas, all!

When Marvel is his family.

my @Marvel fam. Here’s to another 10 years...

His gentle reminders will be the death of us.

Gentle reminder... We’ve got this special ‘LITTLE’ film coming out next April... @avengers #ENDGAME #TeamStark

Happy Birthday, Robert Downey Jr!