Prospectus by Investment Company (Form 497)

MML SERIES INVESTMENT FUND II

MML Invesco Discovery Large Cap Fund

Supplement dated March 4, 2026 to the

Prospectus dated April 25, 2025 and the

Summary Prospectus dated April 25, 2025

This supplement provides new and additional information beyond that contained in the Prospectus and Summary Prospectus, and any previous supplements. It should be retained and read in conjunction with the Prospectus and Summary Prospectus, and any previous supplements.

Effective immediately, the following information supplements the information found under the heading Portfolio Manager(s) in the section titled Management (on page 26 of the Prospectus):

Ido Cohen is a Portfolio Manager at Invesco Advisers. He has managed the Fund since February 2026.

Effective immediately, the following information supplements the information for Invesco Advisers, Inc. found under the heading Subadvisers and Portfolio Managers in the section titled Management of the Funds beginning on page 99 of the Prospectus:

Ido Cohen 

is a portfolio manager of the MML Invesco Discovery Large Cap Fund. Mr. Cohen is a Portfolio Manager at Invesco Advisers. He has been associated with Invesco Advisers and/or its affiliates since 2010. Prior to joining Invesco Advisers, he was a Vice President at J&W Seligman Investments, where he worked as a Senior Analyst focusing on information technology, media, and telecommunications equities. Prior to joining J&W Seligman Investments, he served as Senior Analyst and Co-Head of the U.S. equities telecommunications research team at Credit Suisse. Prior to joining Credit Suisse, Mr. Cohen served on an investment team focused on technology, media, and telecommunications at Diamondback Capital.

PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE

MMLIIPRO-25-06

DL-25-02

MML SERIES INVESTMENT FUND II

MML Invesco Discovery Large Cap Fund

Supplement dated March 4, 2026 to the

Statement of Additional Information dated April 25, 2025

This supplement provides new and additional information beyond that contained in the Statement of Additional Information ("SAI") and any previous supplements. It should be retained and read in conjunction with the SAI and any previous supplements.

Effective immediately, the following information replaces similar information for the MML Invesco Discovery Large Cap Fund (the "Fund") found under Invesco Advisers, Inc. on page B-126 in the section titled Appendix C - Additional Portfolio Manager Information: 

The portfolio managers of MML Invesco Discovery Large Cap are Ido Cohen, Ash Shah, and Ronald Zibelli, Jr.

Effective immediately, the following information supplements the information for the Fund found on page B-126 under the headings Other Accounts Managed and Ownership of Securities in the section titled Appendix C - Additional Portfolio Manager Information:

Other Accounts Managed:

Ownership of Securities:

As of December 31, 2025, Mr. Cohen did not own any shares of MML Invesco Discovery Large Cap.

PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE

MMLIISAI-25-04