Moeen Ali believes facing South Africa on their home soil is as big a challenge as an Ashes series ahead of the first Test in Durban on Boxing Day.
The Worcestershire all-rounder played an important role in England defeating the Aussies 3-2 last summer.
But now comes the challenge of the Proteas, still ranked the number one Test side in the ICC ratings despite losing the recent series in India.
The 28-year-old said: "“It is going to be up there with the Ashes. To play South Africa in their back yard is going to be tough.
"We are going to have to play really well to win the series against these boys. Hopefully we can do that."
Moeen concedes it was a tough experience against Pakistan bowling-wise in the recent series in the UAE which Engand lost 2-0.
He said: "I felt the Pakistanis played me really, really well and they were the best I've ever bowled at.
"They never once let me settle and knocked me around, which was tough.
“I know it is going to be very tough against South Africa, who in my opinion are also very good players of spin.
"But I felt like I learned so much from the UAE than I had done in the last couple of years before that."