If the sponsors income on it own meets the financial requirements the you need only the sponsors financial evidence. If you need to combine your income to meet the financial requirements then both of you need to include your financial documents.

• 6 months of payslips
• 6 months of corresponding bank statements showing the pay deposits in your account
• a letter from the employer stating the length of employment, position, current salary, if you're full time, etc
• P60
• job contract

In complex situations, other documents may be required.

UKBA Financial Requirements evidence