Alphabet Inc., the owner of Google, has made an offer to acquire Fitbit Inc., according to a report from Reuters.

Both companies declined comment on the rumor, but sources told Reuters that Google has its eye on entering the crowded fitness tracker and smartwatch market. This would be the first wearable for the company.

“There is no certainty that the negotiations between Google and Fitbit will lead to any deal, the sources said, asking not to be identified because the matter is confidential,” the report read. “The exact price that Google has offered for Fitbit could not be learned.”

Shares of Fitbit were up nearly a third—$1.32, or 30.6 percent—to $5.63 at market close Monday.