The Welsh actor, who plays Elton John in the upcoming film Rocketman, took to Instagram before uploading a shot of him dressed as the Candle In The Wind singer.
Stripping down to a pair of skintight golden hot pants, Taron left almost nothing to the imagination as he slumped in a chair.
Going shirtless, he teamed the shorts with a matching golden jacket.
The star completed his look with winged boots and pulled up white and red sports socks.
Taron captioned the shot: “Happy Birthday, Elton John.
“You are just about the most extraordinary person I’ve ever met.
“In honour of your birthday, here’s a photo of me (as you) in some hot pants.”
Within minutes the post was flooded with crude messages due to Taron’s package being impossible to miss.
Another added: “Seriously, Taron. I’m speechless.”
“That bulge is a crime against my ovaries,” a third continued.
Meanwhile, Elton John’s husband David Furnish cheekily replied: “Reminds me of my wedding night…”
Previously chatting to Daily Star Online about the upcoming biopic, the 56-year-old said: “I was down on the set the other day and we have released the first teaser trailer for the film.
“Fingers crossed but I think it is going well.
“I am so happy with everything I have seen so far and I think Taron is doing an unbelievable job.”
Admitting he and Elton would only ever agree to make the film if they would retain control, David, 56, added: “We are producing the film, so of course we have input into everything.
“You don’t do something like this and hand it over to the other people without having a sense of involvement and control.”