THE NORTHWESTERN MUTUAL LIFE INSURANCE COMPANY

NML VARIABLE ANNUITY ACCOUNT A

SUPPLEMENT TO THE PROSPECTUSES

INDIVIDUAL FLEXIBLE PAYMENT VARIABLE ANNUITY (FEE-BASED) (DATED APRIL 30, 2008)

NML VARIABLE ANNUITY ACCOUNT B

SUPPLEMENT TO THE PROSPECTUSES

FLEXIBLE PAYMENT VARIABLE ANNUITY (FEE-BASED) (DATED APRIL 30, 2008)

NML VARIABLE ANNUITY ACCOUNT C

SUPPLEMENT TO THE PROSPECTUSES

INDIVIDUAL FLEXIBLE PAYMENT VARIABLE ANNUITY (NETWORK EDITION)

(DATED APRIL 30, 2008)

This Supplement revises certain information with regard to the internal annuity exchange policies contained in the Prospectuses referenced above dated April 30, 2008.

In the section titled, “Additional Information”, under the heading Internal Annuity Exchanges, the second paragraph is amended as underlined below:

Amounts exchanged from a front-load Contract to a Contract will not be subject to any additional front-end sales charge or withdrawal charge. We currently do not allow an exchange from a variable annuity contract we previously issued to a Contract when amounts exchanged from the previously issued variable annuity contract would be subject to a withdrawal charge, although we may allow such exchanges when there are no applicable withdrawal charges on the Contract being exchanged. Fixed Annuity Contracts, which are not described in this prospectus, are available for exchange to a Contract, however, any applicable withdrawal charge or market value adjustment may be assessed on amounts exchanged from the Fixed Annuity Contract.

Please read this Supplement carefully and keep it with your Prospectus for future reference.

This Supplement is dated August 1, 2008.