TikToker Orla Melissa Sloan, 21, pleaded guilty to stalking the 24-year-old and his former team-mate Billy Gilmour, 21, as well as harassing fellow Blues star Ben Chilwell, 26, at Westminster Magistrates' Court on Wednesday.
The court heard she slept with Mount, who had surgery on a pelvic injury last month, after they met at a party at his England team-mate Chilwell's home in November 2020.
Prosecutor Jason Seetal said they stayed in contact for around six months before Mount "decided that the relationship was not going to progress".
"Upon informing Miss Sloan of this, he has been subjected to a bombardment of messages," he said.
"He began asking her to stop messaging him before blocking the number.
"He then began to receive messages from new numbers and each time he would block those numbers there would be messages from a different number."
Mr Seetal said a total of 21 different numbers were used to contact Mount with some messages including collages of photos of the player with other women.
The court heard that in one message from an Instagram account using the name 'Devil Baby', she said: "I can morph at any time so let me apologise and set things right."
Another showed an Apple account buying a new number for £12.99 with the words: "I'm not buying food anymore so I can get more numbers. I will be faster than you."
Mr Seetal said Mount was "concerned she had an obsession or fixation with him and he didn't know what she was capable of".
In a statement, Mount said: "Miss Sloan knows roughly where I live and where I train.
"I'm worried as if she is unable to contact me she might turn up at my training centre."
The court heard other messages were aimed at professional footballers, friends and family members, including left-back Chilwell.
He told how he found Sloan's behaviour "erratic", while Scotland midfielder Gilmour said her messages had a "huge impact" on his life, after he joined Brighton from Chelsea last September.
"I have not been able to sleep and have had to take sleeping tablets," he said.
"It's had a negative effect on my performance and professional life."
"Being in a new town where I don't have my friends or family, it's really upsetting."
The court heard Gilmour had initially exchanged messages with Sloan before telling her he did not want their contact to continue and did not have a relationship with her.
But she claimed to have fallen pregnant in allegations described in court as "completely fictitious".
"I don't know who I can trust anymore," Gilmour said.
"Some of the information would only have been known by people close to me."
Sloan, from Exeter, pleaded guilty to causing "serious alarm or distress" by stalking Gilmour between September 10 and October 28 last year.
She also admitted stalking Mount between June 19 and October 28 last year, as well as causing harassment to Chilwell between October 20 and October 29, 2022.
District Judge Neeta Minhas adjourned sentencing to June 20 for reports to be prepared, telling her the most serious offence, against Gilmour, crossed the custody threshold.
She was granted unconditional bail.
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