Jennifer Aniston attends the premiere Of HBO's "The Leftovers" Season 3 at Avalon Hollywood. Picture: Bang Showbiz

Jennifer Aniston has admitted she had a secret "stalker account" to learn about Instagram before joining the social media platform earlier this week.

The 50-year-old actress sparked a sensation earlier this week when she revealed she had joined the photo-sharing platform but it seems it wasn't her first experience of the "social media pool" as she wanted to understand how it all worked before she was ready to go public.

She confessed on "Jimmy Kimmel Live!": "It was a stalker account.

"When I was thinking about doing this, I sort of figured it was time to kind of understand the world and dip my toe into the social media pool."

The "Morning Show" actress broke the Guinness World Record for the fastest time to reach 1 million followers after sharing a selfie with her former 'Friends' castmates on Tuesday (15.10.19), taking just five hours and 16 minutes to amass the milestone, and she now has over 11 million watching her posts.

Alongside the blurry selfie, Jennifer wrote: "And now we're Instagram FRIENDS too. HI INSTAGRAM (sic)."

And Jennifer has already mocked the glitches she caused on Instagram with her surge in popularity with a spoof video.

She captioned the clip: "I swear I didn't mean to break it. Thank you guys for the kind, glitchy welcome."

The "Cake" star had hinted a few days ago that she was thinking about joining Instagram because she likes the "control" over her life it would offer her.

She teased: "[On social media] you can actually have a little bit more control over the narrative that's out there. [You can] right some wrongs and some silly things that, God knows, are said often. Maybe [I'll join]. You never know."