Robert Downey Jr
Robert Downey Jr shared a paparazzi picture of Tom Hiddleston on Instagram Ian Gavan/Getty

Tom Hiddleston debuted on Instagram and revealed his first look as Loki from the upcoming Marvel movie Thor: Ragnarok. But his move to build-up excitement for his character's return was overshadowed by Robert Downey Jr's hilarious welcome message for him.

Join me in welcoming the biggest T. Stark fan of them all to Instagram! @twhiddleston

A photo posted by Robert Downey Jr. (@robertdowneyjr) on

On Wednesday (9 August) the Iron Man actor poked fun at his Avengers co-star by posting a blurry paparazzi image of Hiddleston wearing an "I Love TS" t-shirt. He captioned the image with "Join me in welcoming the biggest T. Stark fan of them all to Instagram! @twhiddleston."

The picture was taken during the 35-year-old Thor actor's romantic beach escapade with the pop star Taylor Swift in Rhode Island during the Fourth of July weekend. Although Downey Jr interpreted TS as Tony Stark, fans knew he was taking a dig at his colleague's infamous romance with the Bad Blood singer.

The 51-year-old Avengers actor is famous for trolling his colleagues and fans on social media. Two months back he poked fun at Captain America actor Chris Evans on his Instagram account. Downey Jr wore a similar t-shit that Evans wore in one of his films and posted the image the image sharing site and wrote: "Who wore it better? Chris is trying but let's be honest, you want to be twinsies with me."

Earlier this week, he confused his followers by sharing a fan-made poster from Avengers Infinity War Part I and II hinting at a possible merger between the Marvel Cinematic Universe and Marvel TV Universe.

In July 2016, Hiddleston confirmed his romance with the 26-year-old American singer, soon after her split from Scottish DJ and record producer Calvin Harris.

Hiddleston is currently filming in Australia for the third instalment of Thor. The actor joined Instagram and posted Loki's first look and captioned it "he's back!" Since then, the picture has received thousands of likes.

He's back!

A photo posted by Tom Hiddleston (@twhiddleston) on