The 63-year-old businessman bemoaned the "total garbage" that he predicted would be printed tomorrow following English's appointment to YouView, an "exciting" on-demand TV site that he was appointed chairman of back in March.
As speculation grew about the reasoning behind the 31-year-old's move, Sugar explained on Twitter: "Media asked if there was a problem/conflict with Stella at [original company] Viglen.Total garbage,expect lies tomorrow.Unbelivable negative world we live in (sic)."
He added: "That's the beauty of twitter I can tell you the real story on Stella, with 600k followers that's more than the circulation of some papers."
English, a former manager at a Japanese investment bank, beat rival Chris Bates to a £100,000 job with Sugar in the series six final of The Apprentice last December.
She said after her win: "I'm so excited about the future. It's all been worth it, all that blood, sweat and tears... I'm just so happy."
English previously described her success on the reality show as "phenomenal".
The seventh series of The Apprentice, which will see the winner start a business with Lord Sugar, continues Wednesday at 9pm on BBC One.
Watch Lord Alan Sugar choose Stella English as his next Apprentice below.