The TV presenter appeared at Cheltenham Magistrates Court on Wednesday for sentencing.
A judge also fined Knowles almost £1,500 after he previously pleaded guilty to the two driving offences.
He was caught driving at 85mph in a 70mph zone while driving his Range Rover on the A417 Brockworth Bypass on January 28.
Knowles also told magistrates that he been using his mobile phone, despite having a hands-free kit, due to a “dodgy power lead”.
He received six points on his licence for the offence, which resulted in a driving ban as he already had six points on it.
Presiding justice Andrew Hill told Knowles, from Cirencester, Gloucestershire, the ban would be enforced as it would not cause him “exceptional hardship”.
Hill told him: “We take into account that you have shown remorse.
“We will disqualify you from driving today and you will be disqualified from driving for six months.
“From this moment in time, you are not able to drive any motor vehicle in any public place.”
Knowles asked: “I can drive home, right?”
Hill replied: “No.”
Knowles then told him: “I’m joking.”
He was fined £666 for speeding and £666 for using his phone, with a victim surcharge of £66 and prosecution costs of £85.
Speaking after the case, Knowles said: “For me, this was a wake-up call and me putting my phone in the boot of my car now stops the temptation.
“The six-month ban was appropriate because to give anything else would be giving me special privilege.”