Fans freak out over Reese Witherspoon, Jack Black and more stars' 'awkward' throwback photos

Reese Witherspoon has shared an adorable photo from her teenage years for a good cause. The Legally Blonde star has posted the throwback photo on social media to support the Puerto Rico relief efforts, following the aftermath of Hurricane Maria.

Taking to Instagram, the 41-year-old actress posted the snap which shows her with her eyes closed while smiling for the camera wearing a red dress and dorky prescription glasses.

"Here you go @nickkroll... giant glasses, awkward hands, feeling 14! All for a good cause. God Bless Puerto Rico. #PuberMe #PuertoRicoRelief," Witherspoon wrote alongside the picture that she shared on the photo-and-video-sharing application.

The image has already garnered more than 347,000 likes, with her fans loving the blast from the past photo of the actress.

"This is the best! Adorable," a fan said, while another added, "Ohhhh I love 14-year-old Reece! You look just as beautiful as today."

A fan said, "What would you give to be able to go back and give your 14 year old self a hug and tell her how remarkable she was," while another put, "Oh for goodness' sake Reese - you still look cool in this (which I'm sure you were) - how is that even possible?!"

Witherspoon is not the only star to share a throwback photo after Nick Kroll and Stephen Colbert launched the #PuberMe challenge. Colbert has promised to donate $1,000 for every awkward picture posted on Twitter or Instagram by celebrities with the hashtags #PuberMe and #PuertoRicoRelief.

Kroll and Colbert have shared throwback photos of themselves on Instagram. Kroll is seen striking a pose in a shimmery silver jacket paired with a black shirt and black trousers, while Colbert is seen sporting jacket and tie, which probably was his school outfit.

"@stephenathome is raising money for Puerto Rico, donating money for every #PuberMe photo shared by celebs. Encourage your faves to get involved! #tbt," Colbert wrote next to the photo.

Jack Black has shared a black and with mugshot taken when he was a teenager. The comedian wrote, "#puberme #puertoricorelief."