JENNIFER Garner has become the meme queen of the 2018 Oscars after her shocked facial expression went viral.

The 45-year-old star left viewers baffled after she was spotted clapping her hands before suddenly pulling a horrified look, reports The Sun.

The moment has left fans devising a number of theories over what the star had noticed, or even remembered.

“Jennifer Garner has just realised she’s left the iron on,” one joked.

Another chimed: “Jennifer Garner has just realised she’s left her straighteners on.”

Others reckoned the star had forgotten to “switch off the oven” before making her way to the glamorous bash.

The meme means Garner has stolen the Oscars meme crown from Nicole Kidman, who left viewers in stitches with her awkward seal-like clap last year.

Explaining the reason behind her comical applause when speaking to Kylie and Jackie O, she revealed it was the result of her very expensive jewellery.

She confessed: “So therefore I’m clapping but it was really difficult because I had this huge ring on which was not my own but was absolutely gorgeous and I was terrified of damaging it!”

But it wasn’t just Garner’s stunned expression that left fans talking, as the actress also won a string of praise for her red carpet style.

The actress looked stunning in a cobalt blue Atelier Versace gown and glam drop earrings which cost a whopping $US605,000 ($782,000), according to the New York Post.

They claim she also paired her Grecian gown with two Piaget rings, priced at $US28,600 ($36,000) and $US192,000 ($248,000) a piece.