Would-be students at Cambridge University will have to sit written tests as part of the application process, the university's admissions director has announced.
The move will affect students applying for courses starting in autumn 2017.
The tests will be tailored to each subject and will be taken before or at interviews, said Dr Sam Lucy in a letter to UK schools and colleges.
The aim is to maintain fairness during qualification reform, said Dr Lucy.
The first tests will be sat by applicants in November this year, says the letter.
This is when a major overhaul of England's exams system will mean sixth-formers have sat the first batch of new GCSEs and will be taking new A-level courses in some subjects.
Cambridge University has been outspoken about government plans to separate AS-levels from A-levels to form a stand-alone qualification.
It says AS-levels are the best predictor of how well a student will perform in every subject except maths.
In November 2014, it wrote to schools and colleges urging them to continue to offer AS-levels - but while some schools and colleges have opted to keep AS-levels and teach them alongside A-levels, others have decided to drop them and to focus instead on A-levels.
In the letter Dr Lucy said the new tests would provide "valuable additional evidence of our applicants' academic abilities, knowledge base and potential to succeed in the Cambridge course for which they have applied".
"This move is a result of responding to teacher and student feedback, a desire to harmonise and simplify our existing use of written assessments and a need to develop new ways to maintain the effectiveness and fairness of our admissions system during ongoing qualification reform," Dr Lucy said.
The letter says no advance preparation will be needed, "other than revision of relevant recent subject knowledge where appropriate".
Most at-interview assessments will be an hour long and most pre-interview assessments will be no longer than two hours.
Cambridge says it will schedule its pre-interview tests to coincide with Oxford's to make them easier for schools and colleges to administer.
The at-interview assessments will take place during the December interview period, usually on the same day as the interviews.
A university spokesman said the new tests would complement existing assessment measures which include a supplementary application questionnaire, examples of written work, teacher references and academic interviews.
The changes to AS-levels would mean the loss of "a key piece of evidence in the mix", which the tests are designed to replace, said the spokesman.
"We are looking at how people think [...] We will see how people are at interview but also how they are in a written assessment."
The spokesman said the new tests would be university-wide and would replace tests run in some subjects by individual colleges.
They are not a return to entrance exams, abolished in the 1980s, which students had to pass before being invited for interview, said the spokesman.