Just five days after the 41-year-old actress officially joined Twitter, the supermodel sent a sweet tweet to her pal, with whom she recently costarred in the Nick Cassavetes-directed flick, The Other Woman.
"I am SO excited the most amazing person has FINALLY joined twitter!! @CameronDiaz" the 21-year-old stunner wrote.
To which Diaz adorably replied, "I miss you so much little lamb!" and added some heart emojis.
This isn't the first time Upton has gushed over her close friend. She previously told E! News that her costars Cameron and Leslie Mann were "the most inspirational and amazing women" to work with on the forthcoming comedy, which is due to hit theaters in April 2014.
Diaz has been rather chatty since joining the social media site, recently sharing a photo of herself in character as Miss Hannigan on the set of the Annie movie remake.
"I want you to meet someone. Her name is Ms.Hannigan. She ain't nice and she ain't pretty," the actress wrote on Tuesday, Nov. 12, captioning a photo of herself dressed in character as the cruel orphanage supervisor in which she's sporting dark lips, heavy eyeshadow, large hoop earrings and several chain necklaces.
Earlier this week, the Shrek star was snapped all smiles on the set of the upcoming flick in Harlem, where she was seen filming with costar Jamie Foxx, who costars as the Daddy Warbucks-esque Benjamin Stacks.
Will Smith and Jay Z are producers on the project, which also stars Quvenzhané Wallis as the titular character as well as Rose Byrne and Bobby Cannavale and is set to hit theaters on Christmas Day 2014.